Polymyalgia rheumatica (PMR) is an inflammatory disorder characterized by severe proximal myalgias associated with an elevated erythrocyte sedimentation rate (ESR). In this report 10 otherwise typical PMR patients with an ESR <35 mm/hr, and 10 PMR patients with an ESR > 35 mm/hr were examined and prospectively followed. We report the initial laboratory response to steroids in both groups as well as follow-up (average32.6 months in the low ESR group). The average follow-up for this study is the longest reported for low ESR PMR. The most significant difference noted was a longer duration before diagnosis and therapy for the low ESR group. Both groups showed similar clinical and laboratory response to therapy and similar post-treatment disease duration.The absence of an elevated ESR does not exclude the diagnosis of PMR. Clinical response to steroids and a drop in the ESR after therapy are proposed as useful to confirm the diagnosis.