In this study, the effects of florfenicol and tulathromycin on clinical recovery and acute-phase proteins in bovine respiratory diseases (BRD) were evaluated under the field conditions. A total of 30 local race feedlot cattle were used in the study. Twenty naturally infected beef and 10 healthy beef were used for the experimental and control groups, respectively. Sick animals were randomly divided into two groups of 10 and subcutaneously 40 mg per kg florfenicol was administrated in group I and 2.5 mg per kg tulathromycin was administrated in group II as single dose. The animals were clinically examined before (0 h) and 9 days after the treatment. Also, blood samples were taken and serum haptoglobin and serum amyloid A concentrations were measured before and 9 days after the treatment. It was concluded that although the clinical findings and recovery were not always correlated with serum acute phase proteins levels, florfenicol and tulathromycin can be effective for BRD therapy under field conditions.