Feared by every surgeon, retained surgical sponges (or gossypiboma) are rare iatrogenic entities. Ultrasonography and computed tomography are very valuable, providing an immediate answer in the majority of cases. We report 12 cases of intra-abdominal retained surgical swabs. The ultrasonic pattern was made whether of a large poorly echogenic mass with a hyper-echogenic center and sharply delineated posterior acoustic shadow (7 cases) or of a large acoustic shadow posterior to a solitary highly echogenic area (4 cases). Computed tomography demonstrated whether large peripherally enhanced cystic mass associated with serpiginous or spongiform central area (5 cases) or heterogeneous abscess-like fluid mass.