Background: Pulmonary function testing is not feasible in many adults with intellectual disabilities, because of difficulties with understanding and cooperation. Aims: To investigate feasibility, repeatability and reproducibility of measuring airway resistance using the interrupter technique (MicroRint) in people aged 50 years or over with a mild, moderate or severe intellectual disability. Method: Sixty-seven participants were recruited through three Dutch care centres. Feasibility (percentage adequate first measurements) as well as repeatability and reproducibility were evaluated using the Intraclass Correlation Coefficient (ICC) and the within subject variation (SDw). Results: The group with a severe intellectual disability was too small for valid analyses and was therefore excluded. Feasibility: in 86.6% of the total study group, 88.2% of the participants with a mild and 89.7% of the people with moderate intellectual disability, the first measurement was successful. Repeatability: In the total study group, the group with a mild and the group with a moderate intellectual disability the ICC values were 0.76, 0.84 and 0.71, respectively, SDw values were 0.11 kPa/l/s, 0.10 kPa/l/s, 0.10 kPa/l/s, respectively. Reproducibility: In the total study group, the group with a mild and the group with a moderate intellectual disability the ICC values were 0.72, 0.67 and 0.72, respectively, SDw values were 0.14 kPa/l/s, 0.15 kPa/l/s, 0.11 kPa/l/s, respectively. Conclusion: Feasibility, repeatability and reproducibility of measuring airway resistance using the MicroRint are good and acceptable in people with a mild or moderate intellectual disability aged 50 years or over. (C) 2009 Elsevier Ltd. All rights reserved.