OBJECTIVES: Helical CT without contrast iscurrently being evaluated for the diagnosis of renoureteralcolic. Ureteral obstruction and other pathologies withsimilar symptoms can be rapidly identified. This studyintends to evaluate the validity of CTh for these patientsand to compare it with the ultrasound technique in orderto consider the CTh as an efficient diagnostic alternativefor these pathologies.METHODS: A diagnostic evaluation study was carriedout between January 2004 and December 2006 in patients with persistent renoureteral colic after standardcare. They were blindly evaluated by ultrasound andCTh, maintaining the follow up until the “gold standard”confirmation. Qualitative variables were described byfrequency and 95%CI and quantitative variables byposition and dispersion measures. The χ 2 test was usedto compare qualitative variables. Validity indicators and95% CI were calculated and compared with McNemartest.RESULTS: 124 patients were studied. Lithiasis and theother diagnosis had frequencies of 59.7% and 40.3%respectively. The percentage of lithiasis obtained byultrasound (92) was 22.8% and by CTh (124) was59.7%.Validity indicators for CTh were superior to 95%, with100% sensitivity and positive predictive value. Ultrasoundspecificity and positive predictive value were 100%, butsensitivity was only 29.6% (p>0.05).CONCLUSION: CTh can be considered a goodalternative diagnostic technique in the renoureteral colicmanagement