Cytomegalovirus (CMV) is one of opportunistic infections post solid organ transplant and remains a cause of morbidity and mortality. Mammalian target of rapamycin inhibitors has a theoretical antiviral advantage compared to conventional immunosuppression. The primary outcome was to assess the viremic response and kidney function in a cohort of kidney transplant recipients (KTRs) with difficult to manage CMV infection when converted to sirolimus. We retrospectively analyzed the outcome of substituting sirolimus for mycophenolate mofetil (MMF) or tacrolimus in 18 KTR with difficult to manage, resistant/recurrent CMV viremia unresponsive or intolerant of standard anti-CMV treatment, or immunosuppression reduction. Safety and feasibility of sirolimus conversion were assessed through studying CMV viral loads, creatinine levels, immunosuppression, antiviral therapy, kidney function, and acute rejection episodes before and after starting sirolimus as well as the sirolimus side effects. Data were collected from the hospital filing system. The Wilcoxon matched-pairs signed-rank test and Friedman test were used for statistical analysis. The area under the curve for Log10 CMV viral load (log10 copies/ml) was significantly higher before than after the sirolimus switch (P = 0.0156). The median number of days on antiviral treatment was reduced after conversion to sirolimus [48 days (0-95); vs. 68 days (21-146)]. Acute rejection occurred more commonly before than after starting sirolimus [n =5 (27.7%) vs. n = 2 (11.1%)]. Median serum creatinine before conversion to sirolimus was 175.5 μmol/L (79-243), and showed no deterioration three months and one year after conversion [148 (69-271) and 162.5 (69-287) μmol/L, respectively, P = 0.002]. The use of sirolimus, often alongside tacrolimus and after discontinuation of MMF, is a useful strategy in treating recurrent CMV viremia without provoking rejection.