Background and Objectives: in a developing country, cost effectiveness is an important consideration. The aim of this study was to investigate the efficiency and safety of mini broncho-alveolar lavage (mini BAL) samples in the diagnosis of newly developed lung infiltrates in mechanically ventilated patients. Methods: fifty mechanically ventilated patients with newly developed lung infiltrates were assessed by mini-BAL and subsequent microbiological examination. An infant Ryle catheter FG-10 was used as the inner catheter, a Nelaton catheter size 18 FG was used as the outer protective catheter and was blocked by sterile K-Y gel instead of the pre-packaged catheters. Results: eighty six percent of samples collected by Mini-BAL technique from mechanically ventilated patients showed positive growth for culture and sensitivity. Thirty percent of patients had bi microbial infection while fourteen had polymicrobial infection. Fungal infection (Candida) was the most frequent isolated pathogen (32%) followed by Gram-negative bacteria (Klebsiella) (30%). Legionella was the commonest isolated atypical bacteria. Conclusion: this study highlighted the mini-BAL technique as a simple, safe, cheap, available and non-invasive bedside procedure for acquiring uncontaminated lower respiratory secretions in patients with newly developed pulmonary infiltrates.