Proximity cues including perspective, motion parallax, etc., are important depth cues besides disparity cue and blur (defocus) cue. Disparity and blur are now known to have important effects on visual comfort when viewing stereoscopic content. However, the effects of proximity cues are still unknown. In order to explore this question, the authors conducted two experiments. In the first one, the instant effects of proximity cues on the visual comfort of 3D stimuli were assessed using relative comparison. There were, in total, three sessions in this experiment, in which all 3D stimuli were compared with different baselines. The results showed that proximity cues also have significant effects on visual comfort when viewing stereoscopic content. Such effects do not vary significantly with disparity cue, blur cue and the selection of baseline stimuli. In the second experiment, the authors further tested the stimuli with proximity cues, and the results were in accordance with many existing literature results when the stimuli were viewed consecutively. Their results suggest that the perspective information and radial optic flow in the proximity cues may increase vergence–accommodation conflict and therefore reduce visual comfort. However, the effects seem to be limited during consecutive viewing. © 2017 Society for Imaging Science and Technology.