Gas-forming pyogenic liver abscess (GPLA) is rare and is associated with a high mortality rate. It is commonly associated with underlying diabetes mellitus (DM). Gas formation occurs as a result of mixed acid fermentation within the abscess by formic hydrogenlyase, an enzyme produced by certain bacteria. Presentations can be nonspecific leading to a delay in diagnosis. Management includes urgent drainage of the abscess. We report three cases of GPLA as a result of Klebsiella spp. and Escherichia coli infections. All three patients had DM and were very sick at presentation. Diagnosis was delayed in one patient and this likely contributed to his death. Hospitalisations were prolonged. These cases highlight the need to consider GPLA in diabetic patients presenting with fever, abdominal pain, nonspecific symptoms or septic shock.