Background: A variety of accessory fissures are present in human lungs. They are usually situated between the bronchopulmonary segments of lungs and develop when adjacent lobules retain some separation from each other during growth. The knowledge of accessory fissures is important during lobectomies, segmental resections and radiological examinations of lungs. Hence, the present work has been carried out to study the incidence, course, completeness and morphological parameters (length and depth) of the accessory fissures of human lungs. Methods: The study was carried out in 92 adult human lungs (46 right and 46 left) in the Department of Anatomy, Gauhati Medical College and Hospital, Guwahati. After collection and preservation in 10% formalin, the lungs were observed for accessory fissures and the incidences were calculated. Also, the course and completeness of the fissures were noted, and the lengths and depths of the fissures were measured using Vernier caliper. Results: In the present study, out of 92 lung specimens, 3 lungs (2 right and 1 left) showed SAF (3.26%), 1 left lung showed IAF (1.08%). Also, out of 46 left lungs, 8 showed LMF (17.39%) and 1 showed A_p–A_t (2.17%). The average length and depth of SAF were 3.13 cm and 2.72 cm respectively, those of IAF were 3.52 cm and 0.11 cm respectively, those of LMF were 4.27 cm and 1.14 cm respectively, and those of A_p–A_t in left lung were 2.25 cm and 1.22 cm respectively. All the accessory fissures belonged to the grade III variety of Craig and Walker’s fissural classification. Conclusion: The incidences of accessory fissures vary among populations and its knowledge helps in the management of different lung pathologies.