Background: Pre-analytical errors account for up to 70% of all mistakes made in laboratory diagnostics, most of which arise from problems in patient preparation, sample collection, transportation, and preparation for analysis and storage. Preanalytical errors influence the total error thus hindering TQM in laboratory, consequently decreasing the accuracy and reliability of the results generated. The frequencies of PAE and sample rejection rates in pediatric clinics are not yet fully understood compared to PAE in adult departments. Such pre-analytical errors (PAE) can affect children’s safety due to delayed clinical decision-making support or discomfort related to repeat blood sampling. This study was conducted with the aim to determine nature and frequency of the occurrence of pre-analytical errorsin pediatric patients.