Pyomyositis, a purulent infection of an individual muscle group, is an infrequent condition, mostly occurring in immunocompromised patients. It is often caused by Staphylococcus aureus and most of the time restricted to a single muscle group, with disseminated presentations being exceptionally rare. We present a case of severe pyogenic myositis with disseminated muscle involvement, presenting as a septic shock in an immunocompromised patient. The case highlights the importance of considering pyomyositis in the differential diagnosis of a patient with hematogenous dissemination of a pyogenic agent and sustained muscle complaints. A prompt radiological diagnosis and a multidisciplinary approach to treatment are often necessary for a good functional outcome.