Objective: To estimate the inter-observer agreement between two independent groups of Radiologists and General Practitioners in the identification of cardiopulmonary findings via standard plain chest radiographs in adults. Materials and Methods: Two groups of independent raters (Radiologists, n=2; General Practitioners, n=5) analyzed 100 chest radiographs according to the technical quality, normality, and 5 specific findings. Cardiopulmonary findings were registered via a script concordance-like test. We calculated agreement between groups with Vanbelle's kappa coefficient (κ2g). Results: The concordance between the groups of radiologists and general practitioners in specific chest x-ray findings (κ2g 0.46, 95 %CI 0.43 - 0.51), image technical quality (κ2g 0.44; 95 %CI 0.35 – 0.53), and normality (κ2g 0.58; 95 %CI 0.44 – 0.72) was weak. Prevalence indices were high in the analysis of chest x-ray normality (min. – max.: 0.59 – 0.85). Conclusions: Kappa coefficients in the determination of normality could have been biased downward due to high prevalence indices. Short time of training in radiology and experience in the field could account for low agreement between the groups.