Sirolimus (SRL) has been used as an alternative immunosuppressant strategy to allow either dose minimization or complete withdrawal of calcineurin inhibitors (CNI) therapy to improve renal outcome. One hundred thirty-one heart and 55 lung transplant patients were converted from a CNI to SRL based immunosuppression, with CNI elimination in 25 patients, and dose reduction in 161 patients. Fifty-six (28%) patients died and 65 (33%) patients had a 25% or more decline in estimated glomerular filtration rate (eGFR) during a median follow-up of 18 months. The three groups (SRL only group n = 25; SRL + tacrolimus n = 94; SRL + cyclosporine n = 67) had an initial improvement in estimated glomerular filtration rate (p = 0.05), with subsequent similar slow decline in mean eGFR (repeated measures ANOVA, p = 0.96). After controlling for important potential confounding variables, the three groups had similar renal outcome (p = 0.40) and overall survival (p = 0.45). In conclusion, the benefits of CNI withdrawal vs. minimization as part of SRL-based regimens are similar with regard to renal outcomes and patient survival.