Percutaneous testicular varicocele embolisation for symptomatic and subfertile males is often preferred over surgical ligation of the gonadal vein due to its minimally invasive approach and reduced complication rate. Glues, coils, vascular plugs, balloons and sclerosants are used in various combinations to achieve sufficient venous occlusion. Here, we report on the first known case of sclerosant material migration beyond the placement of an embolisation coil for treatment of a varicocele, resulting in a left renal vein thrombus. A man in his 20s presented to the emergency department 2 days following uncomplicated left varicocele embolisation with acute left-sided abdominal pain, found to have sclerosant material causing an ipsilateral non-occlusive left renal vein thrombus with extension towards his inferior vena cava on CT. He was treated with 3 months of anticoagulation and follow-up imaging at 3 months showed resolution of this thrombus without renal impairment.