diff --git a/src/libsysprof-analyze/sysprof-time-series.c b/src/libsysprof-analyze/sysprof-time-series.c
index 1f24233a..9ecb5fad 100644
--- a/src/libsysprof-analyze/sysprof-time-series.c
+++ b/src/libsysprof-analyze/sysprof-time-series.c
@@ -150,7 +150,11 @@ sysprof_time_series_get_values (const SysprofTimeSeries *self,
                                 guint                   *n_values)
 {
   *n_values = self->values->len;
-  return &g_array_index (self->values, SysprofTimeSeriesValue, 0);
+
+  if (self->values->len > 0)
+    return &g_array_index (self->values, SysprofTimeSeriesValue, 0);
+
+  return NULL;
 }
 
 static int
diff --git a/src/libsysprof-analyze/sysprof-xy-series.c b/src/libsysprof-analyze/sysprof-xy-series.c
index e6eb5a42..7399bc4c 100644
--- a/src/libsysprof-analyze/sysprof-xy-series.c
+++ b/src/libsysprof-analyze/sysprof-xy-series.c
@@ -169,7 +169,11 @@ sysprof_xy_series_get_values (const SysprofXYSeries *self,
                               guint                 *n_values)
 {
   *n_values = self->values->len;
-  return &g_array_index (self->values, SysprofXYSeriesValue, 0);
+
+  if (self->values->len > 0)
+    return &g_array_index (self->values, SysprofXYSeriesValue, 0);
+
+  return NULL;
 }
 
 static int