To study witnesses' reaction on the site of outside hospital SCA Method: This is a prospective study conducted in 110 patients who suffered from outside hospital SCA with or without witness, over 20, failed resuscitation. We do not include SCA caused by accidents, intoxication or end-stage of known-chronic diseases. Results: Of 110 patients study-population, documented average age is (59.5±18), higher rate (59.1%) belongs to male.