We present the first reported case of B(12) non-responsive methylmalonic acidaemia due to MMAB mutation to undergo an isolated renal transplant for renal failure. At 8 years of age he was listed for a combined liver and kidney transplant following progressive renal impairment. His metabolic control deteriorated with declining renal function and he was commenced on haemodialysis, leading to marked symptomatic and biochemical improvement. He was therefore relisted for isolated cadaveric renal transplant instead. He underwent successful renal transplantation at 12 years of age and now 6 years post transplant he is enjoying a more normal lifestyle with a marked reduction in plasma methylmalonate.