diff --git a/smash/web/templates/subjects/add.html b/smash/web/templates/subjects/add.html
index c8e78745132d3fba7da0ac8307a74761ef8d5276..b3b490c6ce106a9797280c03ec61cc73521ef93f 100644
--- a/smash/web/templates/subjects/add.html
+++ b/smash/web/templates/subjects/add.html
@@ -89,6 +89,36 @@
             $.get("{% url 'web.api.referrals' %}", function (data) {
                 new Awesomplete(document.querySelector("#id_referral")).list = data.referrals;
             });
+
+            var checkDuplicates = function (e) {
+                var first_name = $("input[name='first_name']").val();
+                var last_name = $("input[name='last_name']").val();
+                if (last_name !== "") {
+                    var url = "{% url 'web.api.subjects' 'GENERIC' %}"
+                    url += "?columns[0][data]=first_name&columns[0][search][value]=" + first_name;
+                    url += "&columns[1][data]=last_name&columns[1][search][value]=" + last_name;
+                    $.get(url, function (data) {
+                        subjects = [];
+                        $.each(data.data, function (index, subject) {
+                            if (subject.last_name.toUpperCase() === last_name.toUpperCase() && subject.first_name.toUpperCase() === first_name.toUpperCase()) {
+                                subjects.push(subject);
+                            }
+                        });
+                        if (subjects.length > 0) {
+                            $("#duplicate_warning").css("display", "block");
+                            var content = "There are possible duplicate(s) with the same name:<br/>"
+                            $.each(subjects, function (index, subject) {
+                                content += subject.first_name + " " + subject.last_name + ", born: " + subjects.date_born + ", screening number: " + subject.screening_number + "<br/>"
+                            });
+                            $("#duplicate_warning").html(content);
+                        }
+                    });
+                }
+            };
+            $("input[name='last_name']").after("<div id='duplicate_warning' class='btn-warning' style='display:none'>message</div>");
+            $("input[name='last_name']").on('keyup', checkDuplicates);
+            $("input[name='first_name']").on('keyup', checkDuplicates);
+
         });
 
     </script>