Introduction: Biomass fuel (BMF) usage is a major respiratory health hazard for children in developing countries. Unlike spirometry , lung oscillometry is an effort-independent pulmonary function assessment, ideal for young children. Objectives: To evaluate the impact of cooking fuel type on the lung function of a cohort of preschool children residing in the Colombo and Kandy districts of Sri Lanka. Methods: Following European Respiratory Society guidelines, lung oscillometry was conducted on an interim cohort of 54 preschoolers (mean age 4.15 ±0.94 years; 51.9% male; mean height 103 ±8.98 cm). Participants were categorised by their household cooking fuel type: 30 used firewood (BMF) and 24 used LP gas (non-BMF). Results: Oscillometry measurements were highly feasible in this cohort of preschoolers; 75.3% of children were willing and able to conduct the measurement, and 89.3% of those reports were acceptable. Overall mean airway resistance (R5) was 8.58 ±1.61 cmH2O/L/s, and airway reactance (X5) was -3.82 ±1.26 cmH2O/L/s. There were no significant differences between fuel groups for R5 (p=0.304) or X5 (p=0.303). Furthermore, after adjusting for height in the regression analysis, stove type remained nonsignificant across both parameters. Conclusions: As the first Sri Lankan study to utilise lung oscillometry to evaluate the impact of BMF usage on early childhood lung function, this research provides vital preliminary regional baseline data. While this interim analysis, limited by a small sample size, found no significant association between fuel type and lung function, it successfully demonstrates oscillometry\'s feasibility for paediatric respiratory assessments in Sri Lanka.