Spigelian hernias are uncommon and account for up to two percent of all ventral hernias with no clear sex predilection. They occur in a paramedian region lying within six centimetres cranial to the “Spigelian hernia belt” – a line between both anterior superior iliac spines. These hernias protrude through a defect in the Spigelian fascia i.e. the transversus abdominus and internal oblique fascial layers. The external oblique fascia remains intact explaining why these hernias can evade detection on clinical examination. We would like to present a unique case of a spigelian hernia containing complicated acute diverticulitis of the sigmoid causing necrotising fasciitis. This again demonstrates that these rare hernias can present in an atypical fashion with a variety of complications. Even though surgical approach is the only management strategy advised in the literature, operative approach may not always be appropriate for the patient. Nonetheless it is important to recognise this pathology, familiarise oneself with the anatomy of the region and understand operative strategies.