diff --git a/yli/survival.py b/yli/survival.py
index 9b98827..9f68e54 100644
--- a/yli/survival.py
+++ b/yli/survival.py
@@ -80,7 +80,9 @@ def kaplanmeier(df, time, status, by=None, *, ci=True, transform_x=None, transfo
 	ax.set_ylabel('Survival probability ({:.0%} CI)'.format(1-config.alpha) if ci else 'Survival probability')
 	ax.set_xlim(left=0)
 	ax.set_ylim(0, 1)
-	ax.legend()
+	
+	if by is not None:
+		ax.legend()
 	
 	return fig, ax
 
@@ -174,7 +176,9 @@ def turnbull(df, time_left, time_right, by=None, *, step_loc=0.5, transform_x=No
 	ax.set_ylabel('Survival probability')
 	ax.set_xlim(left=0)
 	ax.set_ylim(0, 1)
-	ax.legend()
+	
+	if by is not None:
+		ax.legend()
 	
 	return fig, ax