diff --git a/apps/zasm/directive.asm b/apps/zasm/directive.asm
index ae1800e..74fd4bd 100644
--- a/apps/zasm/directive.asm
+++ b/apps/zasm/directive.asm
@@ -142,17 +142,27 @@ handleEQU:
 
 handleORG:
 	call	readWord
+	jr	nz, .badfmt
 	call	parseExpr
-	ret	nz
+	jr	nz, .badarg
 	push	ix \ pop hl
 	call	zasmSetOrg
 	cp	a		; ensure Z
 	ret
+.badfmt:
+	ld	a, ERR_BAD_FMT
+	jr	.error
+.badarg:
+	ld	a, ERR_BAD_ARG
+.error:
+	call	unsetZ
+	ret
 
 handleFIL:
 	call	readWord
+	jr	nz, .badfmt
 	call	parseExpr
-	ret	nz
+	jr	nz, .badarg
 	push	bc
 	push	ix \ pop bc
 	xor	a
@@ -163,6 +173,14 @@ handleFIL:
 	cp	a		; ensure Z
 	pop	bc
 	ret
+.badfmt:
+	ld	a, ERR_BAD_FMT
+	jr	.error
+.badarg:
+	ld	a, ERR_BAD_ARG
+.error:
+	call	unsetZ
+	ret
 
 handleINC:
 	call	readWord
diff --git a/tools/tests/zasm/errtests.sh b/tools/tests/zasm/errtests.sh
index 77bb662..596f4c8 100755
--- a/tools/tests/zasm/errtests.sh
+++ b/tools/tests/zasm/errtests.sh
@@ -22,11 +22,15 @@ chkerr "ld a, hl" 2
 chkerr ".db foo" 2
 chkerr ".dw foo" 2
 chkerr ".equ foo bar" 2
+chkerr ".org foo" 2
+chkerr ".fill foo" 2
 chkerr "ld a," 3
 chkerr "ld a, 'A" 3
 chkerr ".db 0x42," 3
 chkerr ".dw 0x4242," 3
 chkerr ".equ" 3
 chkerr ".equ foo" 3
+chkerr ".org" 3
+chkerr ".fill" 3
 chkerr "ld a, 0x100" 4
 chkerr ".db 0x100" 4