Collagen-vascular diseases are a group of conditions, also known as connective tissue diseases, compromising a number of chronic autoimmune disorders. They may any tissue in any part of the body, where the lungs and pleura get involved to a great extent. Collagen-vascular diseases that demonstrate features of interstitial lung disease include rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), progressive systemic sclerosis (PSS), polymyositis-dermatomyosistis (PM-DM), mixed connective tissue disease (MCTD), ankylosing spondylitis, and Sjögren’s syndrome. High-resolution CT (HRCT) is now one of the investigations used routinely in evaluating patients with known or suspected, infiltrative lung diseases. It offers better assessment of the pattern, distribution, and extent of pulmonary parenchymal abnormalities than chest radiographs. It is capable of imaging the lung with excellent spatial resolution, providing anatomic details similar to that available from gross pathologic specimens or lung slices. This study was designed to assess the role of HRCT in the diagnosis of different types of collagen-vascular disease and in the evaluation of the early as well as the advanced changes that occur in the lungs. During this study, HRCT was capable of detecting different findings ranging from subtle changes as bronchiolectasis and pleural thickening, lung attenuation changes as ground-glass opacification, as well as signs of fibrosis in the form of honeycombing and traction bronchiectasis. On analyzing the current study, it is clear that HRCT is capable of helping characterize and determine the extent of interstitial lung diseases associated with collagen-vascular diseases and that it is possible to reach a specific diagnosis of a certain type of collagen disease or at least narrow the differential diagnosis. HRCT is an easy, non-invasive technique that does not carry the risk of the side effects of the intravenous contrast agents and that can be used as a guide for the optimum site of biopsy and also, as a tool to record the interval changes and the effect of therapy during the follow up scans.