This study describes the clinical course of gastroenteritis caused by Campylobacter spp. as a single-infection versus coinfection and the corresponding changes that occur according to the treatment received, in children between 12 and 24 months of age. This descriptive study is based on the data of a pediatric cohort conducted between 2008 and 2011 of 555 children in Lima, Peru. Ninety-six diarrheal episodes with positive cultures for Campylobacter spp. were evaluated. In 52 episodes, empirical antibiotic treatment was started before pathogen isolation. Of these 96 episodes, 64.6% were coinfections with other pathogens. Coinfections were led by Escherichia coli, norovirus, and Giardia. Compared with single-infection episodes, coinfections had a mean symptom duration of 6.6 versus 5.7 days, a mean frequency of bowel movements per episode of 18.9 versus 14.8, and occurrence of vomiting and fever in 24.2% versus 14.7% of patients. Most of the patients with more severe clinical features at diagnosis were prescribed macrolides as empiric treatment. In the single-infection group, symptom duration was 7.2 +/- 3.3 days in the macrolide-treated group and 7.9 +/- 2.7 days in the nonmacrolide group. Diarrhea caused by coinfection appeared to be generally more severe than a single-pathogen. Patients with more severe clinical courses who received macrolides treatment might have had a faster recovery than patients who received nonmacrolides.