Interstitial lung disease (ILD) is one of the most frequent and most serious complications of connective tissue diseases such as systemic sclerosis, systemic lupus erythematosus, dermato- and polymyositis, Sjogren's syndrome, or mixed connective tissue disease. Diagnosis of ILD is often delayed in patients with connective tissue diseases because of the systemic character of the primary condition, restricted physical activity of the patient and insufficient awareness of the physycian. The aim of the current review is to present the up-to-date information on ethiopathology, classification, diagnosis and treatment of ILD in patients with connective tissue diseases.