diff --git a/src/sparsevec.c b/src/sparsevec.c
index 22649cd..6e48f91 100644
--- a/src/sparsevec.c
+++ b/src/sparsevec.c
@@ -70,6 +70,11 @@ CheckNnz(int nnz, int dim)
 				(errcode(ERRCODE_DATA_EXCEPTION),
 				 errmsg("sparsevec must have at least one element")));
 
+	if (nnz > SPARSEVEC_MAX_NNZ)
+		ereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("sparsevec cannot have more than %d non-zero elements", SPARSEVEC_MAX_NNZ)));
+
 	if (nnz > dim)
 		ereport(ERROR,
 				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
@@ -190,6 +195,11 @@ sparsevec_in(PG_FUNCTION_ARGS)
 		pt++;
 	}
 
+	if (maxNnz > SPARSEVEC_MAX_NNZ)
+		ereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("sparsevec cannot have more than %d non-zero elements", SPARSEVEC_MAX_NNZ)));
+
 	indices = palloc(maxNnz * sizeof(int32));
 	values = palloc(maxNnz * sizeof(float));
 
diff --git a/src/sparsevec.h b/src/sparsevec.h
index 673c5b0..1d79957 100644
--- a/src/sparsevec.h
+++ b/src/sparsevec.h
@@ -2,6 +2,7 @@
 #define SPARSEVEC_H
 
 #define SPARSEVEC_MAX_DIM 100000
+#define SPARSEVEC_MAX_NNZ 16000
 
 /* Ensure values are aligned */
 #define SPARSEVEC_SIZE(_nnz)		(offsetof(SparseVector, indices) + MAXALIGN((_nnz) * sizeof(int32)) + (_nnz * sizeof(float)))