INTRODUCTION: Wheezing in children not older than 24 months of age is a frequent event, and viruses are usually the causative agents. The aim of the study was to estimate the prevalence of respiratory viruses in wheezing children who were not older than 24 months of age and who had no history of asthma. METHODS: Fifty-five Mexican children were included in an analytical cross-sectional study. Nasal secretions were obtained by using sterile rayon-tipped applicators to identify the virus by polymerase chain reaction or reverse transcription-polymerase chain reaction: adenovirus, bocavirus, human rhinovirus, influenza virus type A, human metapneumovirus, parainfluenza, rhinovirus, and respiratory syncytial virus. The prevalence of viral etiology was estimated by dividing the frequency of the identified virus by the number of participants. Ninety-five percent confidence intervals for proportions were calculated. RESULTS: Most of the patients were male (35/55, 63.6%). The average time of evolution of wheezing episode was 3 days. The third part of enrolled population were receiving antibiotics. Respiratory viruses were detected in 33 (60%; 95% CI: 46.8-71.9%) out of 55 cases, and viral coinfection was detected in five cases (9.1%; 95% CI: 3.5-19.9%). Human metapneumovirus was the most frequently identified virus (23.6%), followed by bocavirus (14.5%), respiratory syncytial virus and rhinovirus (12.7% each), and to a lesser extent influenza virus type A and parainfluenza. Rhinovirus was the predominant virus in outpatient children (28.6%). In the inpatient emergency room and inhalotherapy room, human metapneumovirus predominated (41.2 and 16.1%, respectively). CONCLUSION: bocavirus and human metapneumovirus were the most frequently identified viruses in Mexican children who were < 2 years of age, suffered from wheezing, and had no history of asthma.