Purpose Current guidelines for tumor lysis syndrome management recommend rasburicase for high-risk patients. Adherence to guidelines has not been well studied, and the correlation between uric acid reduction and clinically relevant outcomes, such as acute kidney injury, remains unclear. Our study aims to describe rasburicase utilization patterns and outcomes in cancer patients with varying risks for tumor lysis syndrome. Methods In this retrospective cohort study, we included cancer inpatients who received rasburicase for tumor lysis syndrome management at two affiliated academic hospitals from 2009 to 2015. Patients were classified by tumor lysis syndrome risk categories prior to drug administration. Primary outcomes included acute kidney injury incidence and renal recovery. Secondary outcomes included uric acid nadir, mortality, and hospital length-of-stay. Results Among 164 patients, 42 (26%) had high-, 63 (38%) had intermediate-, and 59 (36%) had low-risk for tumor lysis syndrome. A total of 94 patients (57%) had existing renal dysfunction prior to rasburicase use. This occurred more frequently in low- (68%) compared to intermediate- (57%) and high- (43%) risk patients ( p = 0.044). A greater proportion of patients in the high-risk group (78%) had renal recovery when compared to the intermediate- (61%) or low- (45%) risk groups ( p = 0.056). Despite a similar length of stay, the high-risk group had a significantly lower 30-day mortality (10%) when compared to intermediate- (25%) or low- (32%) risk groups ( p = 0.029). Conclusions Our results suggest that rasburicase may be frequently prescribed to treat hyperuricemia unrelated to tumor lysis syndrome in cancer patients. Improved education and adherence to guidelines may improve clinical and economic outcomes associated with rasburicase administration.