The aim of this study was to compare the clinical efficacy of a single-dose of gamithromycin (GM) or marbofloxacin (MR) in kids with naturally occurring pneumonia. Thirty-six kids, aged 2–2.5 months, with body weight ranging from 12 kg to 18 kg were presented with clinical signs of pneumonia. The most prominent clinical findings were an increase in the respiratory rate, crackling lung sounds on auscultation, coughing, nasal discharge and an increased rectal temperature. Mannheimia haemolytica and Mycoplasma spp. colonies were isolated from microbiological examination of six transtracheal washes and lung tissues of one necropsied kid. The severity of pneumonia was evaluated by using cumulative clinical score (CCS). The CCS of the 36 kids used in the study were four and above. Kids were randomly divided into two equal groups; the GM group received a single subcutaneous dose of GM at a dosage of 6 mg/kg and the MR group received MR intramuscularly at a dosage of 8 mg/kg as a single-dose. No side effects related to the drugs were detected in either group. All 36 kids were clinically examined 3 weeks after the initiation of the treatment. Clinical signs in both groups were almost completely absent at the end of the study. A single administration of GM or MR was successfully used in the treatment of kids with pneumonia.