Railway induced vibration is an important source of annoyance in residential environments. Annoyance increases with vibration magnitude. However, these correlations between annoyance and physical ratings are weak. This suggests that vibration-induced annoyance is governed by more than just vibration level, and that simple exposure -response relationships alone sometimes do not provide sufficient information for understanding the wide variation in annoyance reactions. Results of investigations made on factors coming into play when considering an exposure-response relationship between level of vibration and annoyance are presented here. Examples of these factors are time of day, situational factors, personal and attitudinal factors. This was achieved using data from case studies comprised of face -to-face interviews (N=931) and internal vibration measurements collected within the study -Human Response to Vibration in Residential Environments‖ by the Un iversity of Salford. This work will be of interest to researchers and environmental health practitioners involved in the assessment of vibration complaints, as well as to planners and consultants involved in the design of buildings and railways. [Work funded by the Department for Environment, Food and Rural Affairs (Defra) UK].