BACKGROUND Primary immunodeficiencies have a low prevalence, but their severity and high risk of mortality require a clinical approach based in diagnostic instruments that allow their early detection. OBJECTIVE To validate the PRIDE scale to determine a high level of suspicion for primary immunodeficiency diseases in Mexican population. METHODS Seventy five patients with suspicion of primary immunodeficiencies (13.9 ±11.8 years-old) were evaluated with the PRIDE scale by specialists in Allergy and Immunology in this cross-sectional study, and their results were compared with the confirmed diagnosis of primary immunodeficiency. RESULTS Kappa concordance coefficient with clinical diagnosis was 0.872, with an standard error of 0.072; CI 95% [0.73-1.013]. The scale showed sensitivity 98.3%, specificity 86.6%, positive predictive value 96.7%, negative predictive value 92.8%, positive odds ratio 7.3358 and negative odds ratio 0.0196. CONCLUSIONS PRIDE scale was concordant with the diagnosis of primary immunodeficiency in the majority of patients with a previous confirmed diagnosis. The characteristics of diagnostic accuracy provide reliability to this instrument in the scrutiny of patients with probable immunodeficiency.