We identified a cohort of 410 patients with connective tissue disorders (CTD) of ≤ 1 year duration among the participating clinics of the Cooperative Systematic Studies of the Rheumatic Diseases Program. Fifty-seven had rheumatoid arthritis (RA), 57 systemic lupus erythematosus, 37 poly/dermatomyositis, 46 scleroderma, and 213 early undifferentiated CTD, including patients with Raynaud's phenomenon, unexplained polyarthritis or at least 3 CTD manifestations such as rashes, myalgias, etc. Baseline clinical data are now being reported. The followup of these patients may prove to be valuable in understanding these diseases. To our knowledge no similar cohort of patients is available for further investigation.