Aims: To define the natural history of patients with suspicious urinary cytology and negative initial evaluation for malignancy in the investigation of haematuria. Patients and methods: Data from the hospital information support system on urinary cytology examinations carried out at one centre were audited over a period of 24 months. There were 102 patients who had suspicious urinary cytology for malignant cells with negative initial evaluation. Follow up investigations, treatment, and final outcome were noted. Results: There were 102 patients with suspicious urinary cytology and negative initial evaluation for malignancy in 24 months, with a mean follow up of 15.7 months. Seventy patients had no obvious pathology on initial investigations. Forty one patients were found to have urological malignancies (29 bladder, eight ureteric, and four prostate) on follow up. All patients diagnosed as having urothelial malignancies on follow up had either persistent suspicious cytology (29) or recurrent haematuria (eight). The mean duration for appearance of lesions was 5.6 months (range, 3-12 months). Three patients had suspicious digital rectal examination and biopsies confirmed adenocarcinoma of the prostate. One patient had urinary retention and transurethral resection of prostate showed prostatic adenocarcinoma. The presence of suspicious cells on repeat urine analysis was the only significant factor in predicting the presence of urothelial tumours (p = 0.002). Conclusion: Patients with persistent suspicious/positive cytology or recurrent haematuria need further evaluation and follow up. Asymptomatic patients or patients with obvious benign pathology do not require repeat evaluation. Careful urological evaluation, including prostate, should be carried out in these patients.