Interstitial lung disease (ILD) has a poor prognosis in a significant number of patients with connective vascular disease (CVD). By bronchoalveolar lavage fluid (BALF) analysis, ILD may be demonstrated in nearly half of patients with CVD prior to any alteration in lung function or chest radiograph. High neutrophil and eosinophil counts are usually associated with a high risk of functional deterioration, whereas the presence of increased lymphocytes correlates with a better outcome. Furthermore, initiation of therapy (steroids and/or cytotoxic agents) early in the course of disease is predictive of a better response. Cell differentials in bronchoalveolar lavage (BAL), together with measurements of cell by-products and techniques such as high resolution computed tomography, may contribute in the near future to help characterize those patients with the highest risks of evolution to pulmonary fibrosis, and to determine the most favorable time in the course of the disease for the initiation of therapy.