66 year old patient was diagnosed with macroprolactinoma and started on treatment with Cabergoline at a dose 250 μg twice weekly. Initial echocardiogram was normal and CT chest showed clear lung fields except mild left upper zone consolidation. During a routine follow up appointment 8 months after the initiation of treatment, the blood tests showed abnormal renal function and prolactin level was controlled. CT KUB showed features suggestive of retroperitoneal fibrosis leading to bilateral hydronephrosis requiring bilateral ureteric stent insertion. Following additional investigations guided by the renal MDT team, a conclusion was reached that retroperitoneal fibrosis was secondary to Cabergoline treatment. Patient was switched to Quinagolide but did not receive steroids. A CT scan performed 3 months following the cessation of cabergoline showed partial resolution of Retroperitoneal fibrosis reinforcing the above conclusion. Although cabergoline is associated with pulmonary, cardiac and retroperitoneal fibrosis, current consensus is that these complications occur at higher doses used to treat Parkinsons disease and not reported in treatment of prolactinomas. Current literature does not show an excess risk of fibrotic reactions during treatment with cabergoline at a dose of less than 2 mg a week. Current advice is to obtain echocardiogram before the initiation of treatment and to arrange annual cardiac exams if the above dose is exceeded. There is no guidance on monitoring of renal function. Our case suggests possibility of developing Retroperitoneal fibrosis on treatment with small dose of cabergoline for a relatively short time. It argues the point for including baseline renal function prior to initiation of treatment and monitoring thereafter irrespective of dose of the Cabergoline used.