Objectives: Tacrolimus extended-release formulation has been approved for use in Canada since October 2008. In initial studies, efficacy and safety profile were demonstrated as similar for both formulations (twice-daily tacrolimus and extended-release formula tacrolimus). To validate the safety and efficacy of extended-release formula tacrolimus, we conducted a prospective observational study. Materials and Methods: At our institution, between January 2009 and January 2010, the switch from tacrolimus to extended-release formula tacrolimus was done in 130 stable kidney recipients. Clinical data were accessed at baseline (data before conversion), 1 to 2 weeks, 1 month, 3 months, 6 months, 12 months, and 24 months after conversion. Results: One hundred thirty renal transplant recipients were included in the current study. During the observation period, we saw no acute rejection and no change in graft function (mean serum creatinine levels remained stable). However, compared with baseline, mean tacrolimus trough levels were significantly reduced at 1 to 2 weeks, at 1 month, 6 months, 12 months, and at 24 months after conversion. Regarding the safety profile, no significant changes were noted in blood glucose, potassium, and magnesium. Approximately 35% of recipients preferred the extended-release formula tacrolimus to twice-daily tacrolimus. Conclusions: Conversion from twice-daily tacrolimus to extended-release once-daily tacrolimus appears to be safe and convenient up to 2 years after conversion in some recipients.