diff --git a/bwt.c b/bwt.c
index 38a3c21..a19f6d8 100644
--- a/bwt.c
+++ b/bwt.c
@@ -56,7 +56,7 @@ void bwt_cal_sa(bwt_t *bwt, int intv)
 	bwt->sa_intv = intv;
 	bwt->n_sa = (bwt->seq_len + intv) / intv;
 	bwt->sa = (bwtint_t*)calloc(bwt->n_sa, sizeof(bwtint_t));
-	if (bwa->sa == 0) {
+	if (bwt->sa == 0) {
 		fprintf(stderr, "[%s] Fail to allocate %.3fMB memory. Abort!\n", __func__, bwt->n_sa * sizeof(bwtint_t) / 1024.0/1024.0);
 		abort();
 	}