Background. Many researchers contact colleagues in order to obtain re-prints of their papers. Most people, these days, use electronic aids to do this. Aim. The aim of this study was to compare the success rates for obtaining re-prints using such electronic communication with those obtained previously by post. Method. A hundred requests for e-prints or re-prints were sent electronically to colleagues, and the response rates recorded. Results. Of those approached, 79% responded to the requests, although 12% of these needed a reminder. Those replying electronically without a reminder (41%) took an average of one day to respond (range 0-13 days), whereas those replying by mail without a reminder (26%) took on average nine days (range 2-34 days). Responders needing a reminder (12%) took on average 41 days to respond (range 32-71). There were no significant differences between the response rates of American and British researchers, nor between those of men and women, but there was a significantly higher response rate from colleagues who were sent accompanying materials with the request. Conclusions. These results indicate that rapid replies were received from people responding electronically and that the overall response rate was somewhat higher, and somewhat faster, than that found in most previous postal studies. However, the problem of non- and late-responders still exists. One further advantage for the electronic system is that, unlike the postal method, it facilitates rapid additional communication between the sender and the recipient.