Splenic rupture is a common complaint encountered in emergency surgery. Trauma is the most common cause of splenic rupture, while non-traumatic or occult splenic rupture (OSR) is a rare condition. The differential diagnosis weighs on treatment that ranges between close monitoring, splenorrhaphy, splenic conservation and splenectomy. We report a case of an 63-year-old man presenting with acute atraumatic left upper quadrant pain. Preliminary diagnosis was subsequently determined to be a hematoma secondary to OSR. More accurate detailed history revealed a previous trauma, which occurred more than one year before and mimicked an OSR. Delayed and occult splenic rupture are as different diagnosis as different treatment. Even in emergency surgery, the key for a target therapeutic strategy should consider an accurate diagnostic time.