ABSTRACT Anatomical configurations where the viscero-atrial structures do not follow the usual arrangement or mirror-imaged arrangement is described conventionally as heterotaxy. Isomerism in the context of the congenitally malformed heart is a situation where some paired structures on opposite sides of the left–right axis of the body are, in morphologic terms, symmetrical mirror images of each other. It encompasses two separate entities, right and left isomerism, the former being usually associated with asplenia and the latter with polysplenia. We report herein a rare case of left isomerism that is associated with asplenia in a 4-year-old girl.