To evaluate a possible relationship between urinary tract infections (UTI) and diurnal incontinence (DIC), we studied 251 girls aged 4 years or more who were referred with a history of recurrent UTI and/or DIC. During follow up (mean 35 months), 110 girls (44%) had both UTI and DIC, 50 (20%) only infections, and 41 (16%) only DIC whereas 50 (20%) had neither infection nor DIC. In 110 girls with infections occurring with intervals of at least 6 and 12 months, DIC was definitively initiated by infection on 32 (19%) occasions. Most girls were continent before the infection occurred. When the girls remained free of infection for 6 or 12 months respectively, the frequency of DIC remained unchanged. In conclusion, no support for the concept of DIC leading to UTI was obtained, whereas the reverse was found in some cases and suggested in others.