The presence of inflammatory cells on bronchoalveolar lavage is often used to predict disease activity and the need for therapy in systemic sclerosis-associated interstitial lung disease. To evaluate whether lavage cellularity identifies distinct subsets of disease and/or predicts cyclophosphamide responsiveness. Patients underwent baseline lavage and/or high-resolution computed tomography as part of a randomized placebo-controlled trial of cyclophosphamide versus placebo (Scleroderma Lung Study) to determine the effect of therapy on forced vital capacity. Patients with 3% or greater polymorphonuclear and/or 2% or greater eosinophilic leukocytes on lavage and/or ground-glass opacification on computed tomography were eligible for enrollment. Lavage was performed in 201 individuals, including 141 of the 158 randomized patients. Abnormal cellularity was present in 101 of these cases (71.6%) and defined a population with a higher percentage of men (P = 0.04), more severe lung function, including a worse forced vital capacity (P = 0.003), worse total lung capacity (P = 0.005) and diffusing capacity of the lung for carbon monoxide (P = 0.004), more extensive ground-glass opacity (P = 0.005), and more extensive fibrosis in the right middle lobe (P = 0.005). Despite these relationships, the presence or absence of an abnormal cell differential was not an independent predictor of disease progression or response to cyclophosphamide at 1 year (P = not significant). The presence of an abnormal lavage in the Scleroderma Lung Study defined patients with more advanced interstitial lung disease but added no additional value to physiologic and computed tomography findings as a predictor of progression or treatment response. Clinical trial registered with www.clinicaltrials.gov (NCT 000004563).