diff --git a/backend/dm200.c b/backend/dm200.c
index 994e7f7e..db3387b5 100644
--- a/backend/dm200.c
+++ b/backend/dm200.c
@@ -799,7 +799,7 @@ int data_matrix_200(struct zint_symbol *symbol, unsigned char source[])
 		}
 	}
 	calcsize++;
-	
+
 	if(calcsize <= optionsize) {
 		symbolsize = optionsize;
 	} else {
@@ -810,6 +810,19 @@ int data_matrix_200(struct zint_symbol *symbol, unsigned char source[])
 			strcpy(symbol->errtxt, "Data does not fit in selected symbol size");
 		}
 	}
+
+	if(symbol->option_3 == DM_SQUARE) {
+		/* Force to use square symbol */
+		switch(symbolsize) {
+			case 2:
+			case 4:
+			case 6:
+			case 9:
+			case 11:
+			case 14:
+				symbolsize++;
+		}
+	}
 	
 	H = matrixH[symbolsize];
 	W = matrixW[symbolsize];
diff --git a/backend/zint.h b/backend/zint.h
index 03fb5528..a0b02c8d 100644
--- a/backend/zint.h
+++ b/backend/zint.h
@@ -151,6 +151,8 @@ struct zint_symbol {
 #define KANJI_MODE	3
 #define SJIS_MODE	4
 
+#define DM_SQUARE	100
+
 #define WARN_INVALID_OPTION	2
 #define ERROR_TOO_LONG		5
 #define ERROR_INVALID_DATA	6