diff --git a/pri_q921.h b/pri_q921.h
index 3ef5566..23bcfdc 100755
--- a/pri_q921.h
+++ b/pri_q921.h
@@ -78,7 +78,7 @@ typedef struct q921_header {
 	u_int8_t	tei:7;		/* Terminal Endpoint Identifier (0) */
 #endif
 	u_int8_t	data[0];	/* Further data */
-} q921_header;
+} __attribute__ ((packed)) q921_header;
 
 /* A Supervisory Format frame */
 typedef struct q921_s {
@@ -98,7 +98,7 @@ typedef struct q921_s {
 #endif
 	u_int8_t data[0];		/* Any further data */
 	u_int8_t fcs[2];		/* At least an FCS */
-} q921_s;
+} __attribute__ ((packed)) q921_s;
 
 /* An Unnumbered Format frame */
 typedef struct q921_u {
@@ -116,7 +116,7 @@ typedef struct q921_u {
 #endif
 	u_int8_t data[0];		/* Any further data */
 	u_int8_t fcs[2];		/* At least an FCS */
-} q921_u;
+} __attribute__ ((packed)) q921_u;
 
 /* An Information frame */
 typedef struct q921_i {
diff --git a/pri_q931.h b/pri_q931.h
index ac77ac7..ee406ba 100755
--- a/pri_q931.h
+++ b/pri_q931.h
@@ -81,7 +81,7 @@ typedef struct q931_h {
 #endif
 	u_int8_t contents[0];
 	u_int8_t crv[3];
-} q931_h;
+} __attribute__ ((packed)) q931_h;
 
 
 /* Message type header */
@@ -94,14 +94,14 @@ typedef struct q931_mh {
 	u_int8_t f:1;
 #endif
 	u_int8_t data[0];
-} q931_mh;
+} __attribute__ ((packed)) q931_mh;
 
 /* Information element format */
 typedef struct q931_ie {
 	u_int8_t ie;
 	u_int8_t len;
 	u_int8_t data[0];
-} q931_ie;
+} __attribute__ ((packed)) q931_ie;
 
 #define Q931_RES_HAVEEVENT (1 << 0)
 #define Q931_RES_INERRROR  (1 << 1)