Objective: to study clinical, subclinical of patient with ventilator associated pneumonia (VAP) at Thai Nguyen National Hospital. Subjects and methods: Cross - sectional description of 33 patients diagnosed with VAP at Thai Nguyen National Hospital from July 2020 to June 2021. Results: Male/Female ratio = 2,67. The mean age of the patients was 57,03 ± 21,282. The mean of the onset time in VAP is 4,88 ± 2,955 days. Clinical symptoms: increased purulent sputum secretion (90,9%), fever (87,9%), in which high fever ≥ 38,5⁰C (66,7%), pulmonary crackles (87,9%). Subclinical symptoms: chest X-ray with pulmonary consolidation (54,5%), diffuse pulmonary infiltrates (42,4%), cavity (3,0%); increased peripheral blood leukocytes ≥ 10 G/l (90,9%); high level of procalcitonin > 2 ng/ml (63,6%). Sputum culture: 88,3% was positive for Gram - negative bacteria, in which A.baumannii (32,3%), K.pneumoniae (32,3%), P.aeruginosa (20,6%). A.baumannii is completely susceptible to Colistin (100%), resistant to most of the other antibiotics; K.pneumoniae is high susceptible to Colistin (100%), Carbapenem (>60%). P.aeruginosa is high susceptible to Colistin, Carbapennem, Vancomycin, Linezolid, Piperacillin/ Tazobactam.