Introduction: A cross sectional study was conducted to study the morphology and morphometry of fetal thymus at different gestational age. This study is useful in determining intrauterine growth retardation as well as different immune system related diseases with relation to decrease fetal size. Material & Methods: The study was carried on medically aborted & stillborn fetuses (N=90) after taking ethical clearance. Thymus was dissected, viewed in-situ and then taken out to make different measurements. Results: All the thymus werelocated in superior mediastinum. They were greyish pink to greyish brown in colour. Some were bilobed, triangular, H shaped or irregular in shape with different extensions. Accessory thymus above thyroid cartilage was also noted. Conclusion: Thymic parameters and morphology in relation to gestational age can be used as a reference value in imaging studies for determining IUGR and immune deficiency diseases. The variations in shape should also be kept in mind during thymectomy.