Background and objectives: Lower respiratory tract infection (LRTI) is one of the major causes of morbidity and mortality in young children and elderly. The most important lower respiratory infection is pneumonia, the fourth leading cause of death. Most cases of bronchitis are of viral etiology. Most common lower respiratory infections are acute bronchitis, chronic bronchitis, and pneumonia; the common causative agents are Streptococcus pneumoniae, Haemophilu influenzae, Enterococcus spp, Klebsiella pneumonia. Aims of the study was to find the common bacterial causes of lower respiratory tract other than acid fast bacilli in Erbil city and to determine if there is any relation between the causative agents with gender of the patients, also to determine the antibacterial susceptibility profile of the bacteria that isolated from patients with lower respiratory tract infection. Method: 250 sputum samples collected from patients suffering from lower respiratory tract infection attending the Microbiology Laboratory of Rezgary Hospital, Raparin Hospital and Par Hospital within period of 6 months (from August 2016 to February 2017). A questionnaire form sheet prepared for each patient who includes the following information: Patient name, age, gender, residence, symptoms, Drug history, past medical history and antimicrobial susceptibility done for each pathogen either by vitek or disk susceptibility tests. Result: From 250 patients only 142 patients showed positive growth, 100 (70.4%) were males and 42(29.6%) were females. Lower respiratory tract infection was mostly seen in age group of (41-50) years. The age range in this study varied between six months and 97 years with mean age (47±25.23) years. All together 10 different species of bacteria were identified, majority of which were gram negative (89.42%). The gram-negative bacteria were: Klebsiella pneumonia (30.29%), Acinetobacrebaumanaii (28.9%), Pseudomonas aeruginosa (11.9%), Escherchia coli (8.45%), Pseudomonas oryzihabitans (4.94%), Serratia marcescens (2.82%) and Proteus mirabilis (2.12%) isolated from sputum samples. The gram-positive bacteria were: Staphylococcus aureus (7.04%), Streptococcuspneumonia (2.12%) and Streptococcus oralis (1.42%) isolated from sputum samples. On performing antimicrobial susceptibility testing, in gram-positive bacteria, they were resistant to Amoxicillin and Penicillin while most of them were sensitive to Tetracycline. While in gram negative bacteria, they were resistant to Amoxicillin and Ampicillin and most of them were sensitive to Amikacin. Conclusion: Most of the isolated bacteria were gram negative which was (89.44%) while (10.56%) were gram positive. The prevalence of lower respiratory tract infection caused by bacterial infection is higher in males than females. Most of the gram positive and gram negative were resistant to most of the common antibiotics that used by the patients. Varieties of pathogens are responsible for lower respiratory tract infection and antimicrobial resistance has become significant public health problem.