INTRODUCTION: This research work evaluated the usefulness of C-reactive protein as a marker of acute phase reaction in children undergoing elective major surgery. The study was carried out at the Pediatric Surgical Unit, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife. Children between the ages of two months to 15 years, who had been diagnosed with conditions that required major surgery electively were recruited into the study. I participated in all the operative procedures. OBJECTIVES: The aims of the study were to evaluate the usefulness of C-reactive protein as a marker of acute phase reaction in pediatric elective major surgery in Ile Ife, Nigeria. MATERIALS AND METHOD: Three mls of blood were collected for C-reactive protein estimation at different time periods, 2 before the surgery and 6 after the surgery. C-reactive protein estimation was done using the ELISA method at the department of Chemical Pathology Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife. Data were expressed as median values and presented as tables and charts. Data analysis was done using Kruskal-Wallis test statistic, Mann-Whitney U test, Spearman’s correlation. A criterion of P <0.05 was used to determine statistical significance. SPSS software version 18 (SPSS Inc, Chicago, Illinois) was used. RESULTS: Forty-four patients were recruited for the study with a median age of 2.75years and an age range of two months to 15years between June 2015 and May 2016. There were 33 males and 11 females with a M:F ratio of 3:1. The results of the median serum C-reactive protein levels from the patients demonstrated that the levels at baseline and induction of anaesthesia were the lowest. The levels started rising from 6 hours post surgery, rose steadily to a peak at 24 hours post surgery and steadily declined till 120 hours post surgery. There was a significant difference in serum C-reactive protein levels across the four different age groups at baseline and induction of anaesthesia. There was significant difference in the serum C-reactive protein levels between the males and the females at induction of anesthesia. There was no significant correlation between the level of serum C-reactive protein and the duration of surgery. There was no significant association between the level of serum C-reactive protein and early post operative complications. CONCLUSION: There was no difference in the level of serum C-reactive protein of children of different age groups who had surgery. There was no difference in the level of serum C-reactive protein of the male and female children who had surgery. The duration of surgery had no effect on the level of serum C-reactive protein and the level of serum C-reactive protein was not useful in determining early post operative complications.