diff --git a/tests/instances.tcl b/tests/instances.tcl
index 5251ffa3..766e820e 100644
--- a/tests/instances.tcl
+++ b/tests/instances.tcl
@@ -249,6 +249,37 @@ proc test {descr code} {
     }
 }
 
+# Check memory leaks when running on OSX using the "leaks" utility.
+proc check_leaks instance_types {
+    if {[string match {*Darwin*} [exec uname -a]]} {
+        puts -nonewline "Testing for memory leaks..."; flush stdout
+        foreach type $instance_types {
+            foreach_instance_id [set ::${type}_instances] id {
+                if {[instance_is_killed $type $id]} continue
+                set pid [get_instance_attrib $type $id pid]
+                set output {0 leaks}
+                catch {exec leaks $pid} output
+                if {[string match {*process does not exist*} $output] ||
+                    [string match {*cannot examine*} $output]} {
+                    # In a few tests we kill the server process.
+                    set output "0 leaks"
+                } else {
+                    puts -nonewline "$type/$pid "
+                    flush stdout
+                }
+                if {![string match {*0 leaks*} $output]} {
+                    puts [colorstr red "=== MEMORY LEAK DETECTED ==="]
+                    puts "Instance type $type, ID $id:"
+                    puts $output
+                    puts "==="
+                    incr ::failed
+                }
+            }
+        }
+        puts ""
+    }
+}
+
 # Execute all the units inside the 'tests' directory.
 proc run_tests {} {
     set tests [lsort [glob ../tests/*]]
@@ -259,6 +290,7 @@ proc run_tests {} {
         if {[file isdirectory $test]} continue
         puts [colorstr yellow "Testing unit: [lindex [file split $test] end]"]
         source $test
+        check_leaks {redis sentinel}
     }
 }