The anatomical knowledge of the fissures and the lobes of the lungs are important for accurate interpretation on xrays and CT scans. During routine dissection of thorax region for 1st year MBBS students, we found incomplete oblique fissure on the costal surface of the left lung, it coursed normally from the posterosuperior part of the hilum (Just above the gap between the pulmonary artery and left principle bronchus). It crossed the posterior border 4 cm below the apex. It then descends forwards across the costal surface and completed only 2/3 part of the costal surface. Further remaining 1/3 part of the fissure was incomplete up to the lower part of the hilum. On the base there was superficial accessory fissure which was measured 3 cm in length. Knowing the frequency of occurrence of a variant fissure in a particular population might help the radiologist clinicians and surgeons to make correct diagnosis to plan, execute and modify surgical procedures and this may reduce the morbidity and mortality rates associated with the lung surgeries.