De novo posttransplant thrombotic microangiopathy (TMA) is a complication of solid organ transplantation, which remains difficult to treat. In many cases, immunosuppressants and particularly calcineurin inhibitors, trigger TMA. Although withdrawing the offending drug may lead to resolution of TMA, graft and patient outcomes are poor. Specific treatments, including plasma exchange, have not gained widespread acceptance in those with fulminant disease and new approaches to the condition are urgently needed. We report a case of posttransplant de novo TMA presenting serially in association with ciclosporin, tacrolimus and sirolimus in a young recipient of a living donor kidney transplant. We describe a patient treated with belatacept, a novel CTLA4 Ig fusion protein, as ongoing maintenance immunosuppression to allow avoidance of conventional agents once associated with TMA. We report excellent early graft outcome, with no adverse events using this strategy. We suggest that belatacept may have a role in this traditionally difficult-to-treat group of patients.