This study is an investigation of the effects of short-term crowding on the invasion of personal space. The analysis was carried out by means of research designed for automatic teller machine (ATM) users in Ankara. The activity, withdrawing money from an ATM, requires certain levels of privacy which may vary with the personal characteristics of the individuals. Among these, sex of the user is considered an important factor. Also, situational variables such as density conditions have an effect on interpersonal distance. The survey was carried out through participant observation and short interviews with the users under two - low and high - density conditions. It was found that personal space was invaded more under high density conditions and when the space was perceived as narrower. However, this did not cause a significant difference in the privacy requirements of the users as they mostly preferred a private space under both density conditions. Sex did not appear to be a dominating factor in this choice although people of opposite sexes tended to keep longer distances between them. The only difference was the females' approach to males which was more distant than males approach to females. Utilizing the findings of this research, appropriate design solutions for an indoor ATM hall were proposed.