This study was carried out to determine the levels of various cytokines (TNF-alpha, IL-6, IL-8) and acute phase proteins (haptoglobin, C-reactive protein, serum amyloid A, alpha 1-acid glycoprotein, lactoferrin, and fibrinogen) in pneumonic calves, to reveal changes in these parameters depending on etiologic factors (bacterial, viral, bacterial + viral) in calf pneumonia, and to determine whether these parameters could be used for diagnosis and prognosis of the disease. The study was carried out on a total of 50 calves consisting of 10 healthy and 40 pneumonic animals aged 1 to 6 months. The pneumonic calves were classified into three groups: bacterial, viral and mixed (bacterial + viral). It was found that the levels of IL-6, IL-8, CRP, and TNF-alpha were statistically higher in the pneumonic calves than in the control group animals. It was found that the increase in levels of Serum IL-6, IL-8, and CRP were highest in the mixed infection group (bacterial + viral) and lowest in the virally infected group. Similarly, serum levels of Hp, CRP, SAA, alpha-1-AGP, and LF were found to be more statistically significant (P <0.01) in the infected calves than in the control group animals, but changes in fibrinogen levels were not statistically significant. Although the TP and ALB levels in the pneumonic calves were numerically higher than the same parameters in the control group, this was not statistically significant (P> 0.05). As a result, this study showed that serum levels of cytokines (IL-6, IL-8, TNF-alpha) and serum concentrations of acute-phase proteins (Hp, CRP, SAA, alpha-1-AGP, and LF) are significantly higher in the pneumonic calves than in the control group calves. Furthermore, the assessment of cytokine and acute phase protein levels can play an important role in the early diagnosis of calf pneumonia. This early diagnosis can help prevent deaths caused by pneumonia, which is the leading cause of major losses, and can also be helpful in the early treatment of pneumonia in the veterinary clinical field.