One of the objective measuresof mental workload is through respiratory method. Respiration is a physiological process mainly related to the exchange of O2 and CO2 from body tissues to the air. The aim of this study is to review respiratory method and mental workload research for developing cognitive workload measurement methods based on a literature study. As acknowledge by authors, there are 28 studies using respiratory approach, with 13 parameters in which the respiratory rate parameter is often used. There are 7 domains and 1 nonspecific domain about the studies. From the literature review, considering its advantages, the respiratory seems to be a promising approach in the study of cognitive workload measurement in particular in Indonesia due to its low cost and practical reasons.