Airborne dust bioaerosols, ammonia and formaldehyde levels were determined inside two different (ventilated and unventilated) wood working shops. Airborne dust was found at mean values of 4.3 and 3.01 mg m⁻³. These levels were higher than that recommended by Egyptian environmental law [1 mg m⁻³ indoor maximum allowable concentration (MAC) for hard wood]. The highest frequency of aerodynamic size distribution of airborne wood dust was detected at a diametre of 4.9 µm which was recorded during a machining operation. Total viable bacteria were recorded at a mean value of 10⁴ colony-forming units (cfu) m⁻³, whereas Gram-negative bacteria were found at very low counts (10¹ cfu m⁻³). Fungi levels were recorded at mean values of 10³ and 10² cfu m⁻³ in ventilated and unventilated shops, respectively. Penicillium, Aspergillus, Cladosporium and yeast species were dominant isolates. Moreover, actinomycetes were found at a mean value of 10³ cfu m⁻³ at both workshops. Ammonia was detected in relatively low concentrations (mean values of 457 and 623 µg m⁻³), whereas formaldehyde was found in relatively moderate concentrations (mean values of 0.42 and 0.64 ppm).