Abstract Indoor radon concentration represents an important public health challenge, for simple and inexpensive measurement devices and methods, suitable for large-scale indoors radon measurements, are required. Nuclear Track Methodology, by using a closed-end cup device as a radon chamber is an attractive option for such large-scale indoor radon measurements. A comparative analysis of the detection efficiency of four different (one commercial and 3 specially designed) passive closed-end cup devices for the measurement of indoor radon concentrations is presented. CR-39 (Lantrack®) polycarbonate was the detector material. The four devices were simultaneously exposed to a mean radon concentration of 860 ± 60 Bq m −3 inside a closed room for periods of one, two and three months. An AlphaGUARD ® radon monitoring system was used to continuously monitor the radon concentration within the room. The chemical etching and reading procedures were carried out following a well-established protocol for indoor radon surveys. The detection efficiency and the exposure-time-response relationship of each of the devices were determined.