During the two year from January 1977 to December 1978, 59 renal allograft transplant patients were studied for perirenal collections. During the second or third postoperative day and then at weekly intervals during the initial postoperative period, serial echograms were obtained. Twenty-five perirenal fluid collections were identified in 24 patients. Twelve lymphoceles, three hematomas, three urinomas, one abscess, and six undetermined collections were found. Small and asymptomatic collections were observed. Twelve lymphoceles were managed by aspiration under ultrasound guidance in five patients, closed external drainage in six patients, and nephrectomy for acute rejection 1 patient. Three patients with hematomas had evacuation and drainage with no recurrence. Among three patients with urinomas, two had Foley catheter drainage and one had uretero-ureterostomy. The patient with an abscess required a nephrectomy. Six small collections were managed consecutively, with spontaneous resolution in four patients. Large or symptomatic collections are managed accordingly. Aspiration or closed external drainage was adequate in most cases of lymphoceles. Exploration, with evacuation and drainage of hematomas, has good results. Minor urine leaks were treated with indwelling Foley catheters; major leaks necessitated surgical repair. An abscess would require drainage or nephrectomy. Small or asymptomatic collections should be treated conservatively. We have also found the routine use of ultrasound scanning postoperatively in renal transplant patients to be of value in early diagnosis and follow-up or perirenal fluid collections.