diff --git a/SMILEBASIC/TEST.txt b/SMILEBASIC/TEST.txt
index 29ff2f1..4208f1a 100644
--- a/SMILEBASIC/TEST.txt
+++ b/SMILEBASIC/TEST.txt
@@ -1,3 +1,44 @@
+
+VAR IFTEST=FALSE
+IF TRUE THEN
+ IFTEST=TRUE
+ENDIF
+ASSERT__  IFTEST, "IF"
+
+VAR IFTEST2=FALSE
+IF TRUE THEN IFTEST2=TRUE
+ASSERT__  IFTEST2, "IF"
+
+VAR ELSETEST=FALSE
+IF FALSE THEN
+ELSE
+ ELSETEST=TRUE
+ENDIF
+ASSERT__  ELSETEST, "ELSE"
+
+VAR ELSETEST2=FALSE
+IF FALSE THEN ELSE ELSETEST2=TRUE:ENDIF
+ASSERT__  ELSETEST2, "ELSE"
+
+
+VAR ELSEIFTEST=FALSE
+IF FALSE THEN
+ ELSEIFTEST=FALSE
+ELSEIF FALSE THEN
+ ELSEIFTEST=FALSE
+ELSEIF TRUE THEN
+ ELSEIFTEST=TRUE
+ELSEIF FALSE THEN
+ ELSEIFTEST=FALSE
+ELSE
+ ELSEIFTEST=FALSE
+ENDIF
+ASSERT__  ELSEIFTEST, "ELSEIFTEST"
+
+VAR ELSEIFTEST2=FALSE
+IF FALSE THEN ELSEIFTEST2=FALSE ELSEIF FALSE THEN ELSEIFTEST2=FALSE ELSEIF TRUE THEN ELSEIFTEST2=TRUE ELSEIF FALSE THEN ELSEIFTEST2=FALSE ELSE ELSEIFTEST2=FALSE ENDIF
+ASSERT__  ELSEIFTEST2, "ELSEIFTEST"
+
 DEF CALLTEST(V)
  RETURN V
 END
diff --git a/SMILEBASIC/compiler.d b/SMILEBASIC/compiler.d
index 0331460..e11a020 100644
--- a/SMILEBASIC/compiler.d
+++ b/SMILEBASIC/compiler.d
@@ -656,7 +656,46 @@ class Compiler
         compileStatements(node.then, sc);
         //もしelseもあるのならば、endifに飛ぶ
         GotoAddr then;
-        if(node.hasElse)
+        /*
+        if 0 then
+        elseif 0 then
+        elseif 1 then
+        else
+        endif
+        push 0
+        gotofalse else
+        goto endif
+        else:
+        push 0
+        gototrue elif1else
+        push 1
+        gototrue elif2
+        goto else
+        elif1:
+        goto endif
+        elif2:
+        goto endif
+        else:
+        endif:
+        */
+        if (node.hasElseif)
+        {
+            then = genCodeGoto();
+            else_.address = cast(int)code.length;
+            GotoFalse else2;
+            foreach(t; node.elseif)
+            {
+                compileExpression(t[1], sc);
+                else2 = genCodeGotoFalse();
+                compileStatements(t[0], sc);
+                genCode(then);
+                else2.address = cast(int)code.length;
+            }
+            if(node.hasElse)
+                compileStatements(node.else_, sc);
+            then.address = cast(int)code.length;
+        }
+        else if(node.hasElse)
         {
             then = genCodeGoto();
             else_.address = cast(int)code.length;
diff --git a/SMILEBASIC/node.d b/SMILEBASIC/node.d
index dcc0e7d..62425a0 100644
--- a/SMILEBASIC/node.d
+++ b/SMILEBASIC/node.d
@@ -247,21 +247,28 @@ class Goto : Statement
 }
 class If : Statement
 {
+    import std.typecons;
     Expression condition;
     Statements then;
     Statements else_;
-    this(Expression condition, Statements t, Statements e, SourceLocation loc)
+    Tuple!(Statements, Expression)[] elseif;
+    this(Expression condition, Statements t, Statements e, Tuple!(Statements, Expression)[] elif, SourceLocation loc)
     {
         super.location = loc;
         this.type = NodeType.If;
         this.condition = condition;
         this.then = t;
         this.else_ = e;
+        this.elseif = elif;
     }
     bool hasElse()
     {
         return !(else_ is null) && else_.statements.length != 0;
     }
+    bool hasElseif()
+    {
+        return !(elseif is null) && elseif.length != 0;
+    }
 }
 class For : Statement
 {
diff --git a/SMILEBASIC/parser.d b/SMILEBASIC/parser.d
index 40009ab..c2a9604 100644
--- a/SMILEBASIC/parser.d
+++ b/SMILEBASIC/parser.d
@@ -78,6 +78,7 @@ class Lexical
         reserved["COMMON"] = TokenType.Common;
         reserved["USE"] = TokenType.Use;
         reserved["EXEC"] = TokenType.Exec;
+        reserved["ELSEIF"] = TokenType.Elseif;
         reserved.rehash();
     }
     this(wstring input)
@@ -708,6 +709,7 @@ class Parser
             flag = false;
             if(type == TokenType.NewLine) break;
             if(type == TokenType.Else) break;
+            if(type == TokenType.Elseif) break;
             if(type == TokenType.Endif) break;
             if(type == TokenType.Label)
             {
@@ -730,6 +732,7 @@ class Parser
         {
             auto type = lex.front().type;
             if(type == TokenType.Else) break;
+            if(type == TokenType.Elseif) break;
             if(type == TokenType.Endif) break;
             auto statement = statement();
             if(statement != Statement.NOP)
@@ -1388,6 +1391,47 @@ class Parser
         }
         token = lex.front();
         lex.popFront();
+        import std.typecons;
+        Tuple!(Statements, Expression)[] elseif = new Tuple!(Statements, Expression)[0];
+        while(token.type == TokenType.Elseif)
+        {
+            token = lex.front();
+            auto elseifcond = expression();
+            if(elseifcond is null)
+            {
+                syntaxError();
+                return null;
+            }
+            token = lex.front();
+            if(token.type != TokenType.Then)
+            {
+                if(token.type != TokenType.Goto)
+                {
+                    //IF expr GOSUBは不可
+                    syntaxError();
+                    return null;
+                }
+            }
+            if(token.type != TokenType.Goto)
+            {
+                lex.popFront();
+                token = lex.front();
+            }
+            if(!multiline && lex.front().type == TokenType.NewLine)
+            {
+                syntaxError();
+            }
+            if(multiline)
+            {
+                elseif ~= tuple(multilineIfStatements(), elseifcond);
+            }
+            else
+            {
+                elseif ~= tuple(ifStatements(), elseifcond);
+            }
+            token = lex.front();
+            lex.popFront();
+        }
         Statements else_;
         if(token.type == TokenType.Else)
         {
@@ -1399,14 +1443,14 @@ class Parser
             if(multiline)
             {
                 else_ = multilineIfStatements();
-                lex.popFront();
             }
             else
             {
                 else_ = ifStatements();
             }
+            lex.popFront();
         }
-        auto if_ = new If(expr, then, else_, lex.location);
+        auto if_ = new If(expr, then, else_, elseif, lex.location);
         return if_;
     }
     Assign assign(wstring name)
@@ -1449,14 +1493,16 @@ class Parser
             }
             if(token.type != TokenType.Colon && token.type != TokenType.NewLine && 
                token.type != TokenType.Semicolon && token.type != TokenType.Comma &&
-               token.type != TokenType.Else && token.type != TokenType.Endif)
+               token.type != TokenType.Else && token.type != TokenType.Endif &&
+               token.type != TokenType.Elseif && token.type != TokenType.Print)
             {
                 syntaxError();
             }
             else
             {
                 if(token.type == TokenType.Colon || token.type == TokenType.NewLine ||
-                   token.type == TokenType.Else || token.type == TokenType.Endif)
+                   token.type == TokenType.Else || token.type == TokenType.Endif ||
+                   token.type == TokenType.Elseif || token.type == TokenType.Print)
                 {
                     print.addLine();
                     break;
diff --git a/SMILEBASIC/token.d b/SMILEBASIC/token.d
index d32fd20..99d3cd8 100644
--- a/SMILEBASIC/token.d
+++ b/SMILEBASIC/token.d
@@ -69,6 +69,7 @@ enum TokenType
     Exec,
     Call,
     Common,
+    Elseif,
 }
 
 struct Token