Using data from a standard health screening questionnaire, researchers in the UK say they have found that one in ten men had paid for sex.
The survey was completed by more than 2500 men at one sexual health clinic between October 2002 and February 2004; their average age was 34.
Most it seems had paid for sex with women, and over half said that they had paid for sex while abroad, while 4 out of 10 said they had paid for sex locally.
Dr. Tamsin Groom, of the Sandyford Initiative in Glasgow says 56% of the men who reported having unprotected sex with a prostitute had a partner.
Just under 2% said they had paid for sex both in the UK and abroad and around 1 in 4 said that they repeatedly used prostitutes.
Most revealing was that almost half (43%) said that they had a current partner when they had paid for the sex and more than half (56%) who said that they had had unprotected vaginal sex already had a partner.
Unprotected vaginal sex was more common among those who paid for sex while abroad, but unprotected oral sex was twice as common among the men who paid for sex locally.
As the authors point out, unprotected oral sex can facilitate the transmission of infection.
While none of the 2,500 men who were questioned was HIV positive, 1 in 5 had a sexually transmitted infection, including gonorrhea, chlamydia and syphilis.
According to the report the European country in which the percentage of men paying for sex was highest was Spain, at 39 percent, while 73 percent of Thai men buy sex; buying sex in Asian countries is more common and is frequently considered to be normal male behaviour, says Groom.
The authors suggest that the figures may be an underestimate of actual behaviour as some men may choose not to reveal whether they have paid for sex.
The survey is reported in the journal Sexually Transmitted Infections.