Today, as a result of an increase in the frequency of food protein-induced allergic proctocolitis (FPIAP), there is a need for studies not only to enlighten the pathophysiology of the disease but also to determine simple, non-invasive markers in both diagnosis, and evaluation of the development of tolerance. No study has been found in the literature about the place of neutrophil/lymphocyte ratio (NLR) and mean platelet volume (MPV), which are easy to calculate and non-invasive markers.The purpose is to determine the relation between NLR and MPV with the diagnosis and development of tolerance in children with FPIAP.In this retrospective cross-sectional study, clinical, demographic symptoms and laboratory findings of patients, monitored with FPIAP diagnosis in allergy and gastroenterology clinics, were acquired from the patient record system. Hemogram values at the time of diagnosis were compared with the values of healthy children of the same age and gender.Among 59 patients diagnosed with FPIAP, males constitute 47.4% and females constitute 52.6%. MPV and platelet crit (PCT) values were significantly high when compared to the control group (n: 67) in FPIAP cases (p < 0.001). Also, MPV and PCT values were significantly high in non-tolerance developing cases when compared to developing ones (p= 0.01).Contrary to NLR, MPV and PCT values have been considered to be good markers in predicting prognosis in cases with FPIAP since they are quick, cost effective and easy to calculate.