The two main chronic obstructive diseases are asthma – affecting 1-18% of adult population – and chronic obstructive pulmonary disease (COPD) prevalent in up to 6% of adults. In both cases the treatment depends on diseases’ severity. In management of these conditions, spirometry and complete blood count are two major monitoring tests. Our aim was to compare blood morphology results and spirometry values between patients in groups of different treatment intensity in asthma and COPD. By measuring that, we expected to study whether asthma/COPD patients have a need of stepping-up their treatment steps. Methods A retrospective analysis of patients admitted in 2013-2019 to an outpatient pulmonology clinic in Łódź (Poland). Spirometry values, complete blood count and information on pharmacological treatment were obtained from archival data. Patients were assigned with disease severity according to present GINA/GOLD recommendations. The study included 125 patients – 47 with COPD (22 females) and 78 with asthma (57 females). Results Among patients with asthma, a positive correlation in white blood cell count (WBC) (r=0,236, p=0.038) and ascending GINA treatment steps was found. Significant negative correlations were shown between ascending GINA treatment steps and FEV1, FEV1%, FVC%, MEF50, MEF50, PEF%. In COPD patients, positive correlations between ascending GOLD treatment groups and white blood cell count, neutrophil count, basophil percentage, platelet count (r=0.346; 0.309; 0.321; 0.401 respectively) were found. Negative correlations were shown between ascending GOLD treatment groups and FEV1, FEV1%, FVC, FVC%, MEF50, MEF50%, PEF, PEF% (r=-0.732; -0.575; -0.705; -0.498; -0.632; -0.558; -0.688; -0.597 respectively). Conclusions Negative correlations between ascending GINA and GOLD treatment steps and spirometry values may suggest that asthma and COPD patients may benefit from stepping-up the treatment steps earlier. Potential advantages of that more intensive treatment needs to be examined in the future