Background: Cathelicidin (LL-37) comprises one of several types of antimicrobial peptides that have a vital role in the innate defense against the urinary tract infection (UTI). Objectives: Is to evaluate the diagnostic role of LL-37 in UTI. Methodology: Urine specimens were collected from 70 patients with clinically suspected UTI and from 20 healthy controls. Culture of urine and sensitivity to antimicrobials were tested. LL-37 urinary levels were measured in all participants using an enzyme-linked immunosorbent assay (ELISA). Results: Based on the results of urine culture, the patient group were classified into: 50 patients with culture positive urine (proven UTI) and 20 patients with culture negative urine (suspected UTI). Urine from all control subjects were culture negative. There is significant rise in the level of LL-37 among proven UTI group in comparison with suspected UTI and control groups (p<0.001), while, there is non-significant increase in the LL-37 level among suspected UTI group when compared with control group. There is a significant positive correlation between LL-37 level and bacterial count among proven UTI group (rho=0.442, P=0.003). ROC curve showing excellent ability of LL-37 to differentiate between proven and suspected UTI (AUC=0.982, P=<0.001). The uropathogenic Escherichia coli was the predominant isolate, n = 22 (44%). 67% of the isolates were multidrug resistant (MDR). There is non-significant relation between LL-37 levels and type of organisms isolated from urine (p=0.54). Conclusion: LL-37 can be considered as a good diagnostic marker for UTI.