This study was conducted on 110 patients who suffer from respiratory tract infections in Samarra General Hospital. The results of isolation and identification show 110 bacterial and yeast isolates. The results of isolation and diagnosis showed that 32 isolates of Staphlococcus aureus were obtained, with a percentage of 29%. Klebsiella pneumonia 27(%24.5), Pseudomonas aeruginos and Haemophilus influenzae 13isolates with a percentage of 11.81%. ten isolates of Streptococcus pneumonia and eight of Streptococcus pyogenes in 9.09% and 7.2% respectively. 7 isolates of candida albican. The study showed a significant difference in the incidence of bacterial infection according to gender, the infection rate among males was 73%, from 73 samples out of the total samples, with a number of 78 isolates, As for females, the rate of infection was 27%, from 27 samples, and the numbers of isolates were 32. The ages of the infected patients ranged from 10 to 80 years. The highest number of isolated bacterial and fungal species was within the age groups 50-60 years, and the lowest was above 70 years. C-reactive protein test and some hematological parameters were performed. The results showed different values between patients and the normal range. The results showed that most of the bacterial isolates were resistant to antibiotics, Ampicillin, Oxacillin, Clindamycin, Gentamicin, Ceftriaxone and Trimethoprime while all the isolates were sensitive to Meropenem, Imipenem, Amoxiclave, Ciprofloxacin and Levofloxacin while their resistance to Azethromycin, Erythromycin are variable.