Researchers from the University of Sussex examined data from almost 500 women, some of whom were taking the drug, and some of whom were taking a placebo.
The drug - which blocks the effect of the female sex hormone oestrogen - did cause some symptoms similar to those experienced by women entering the menopause.
While the body was being denied the hormone, which normally plays a role in sex drive, it is thought that the drug itself may have compensatory effects on the uterus and brain.
More tamoxifen patients reported that they were still having sex than those taking the placebo - and fewer taking the drug were having mood swings.
Wonder drug
Tamoxifen has been hailed as a "wonder-drug", which has contributed to the fall in breast cancer deaths over the past decade.
It can help women whose breast tumour contains cells which respond to the hormone oestrogen, stopping cancers removed by surgeons from coming back by denying the cells the oestrogen they need to trigger growth.
However, some women had been put off by the fears that it could wreck their sex lives, with some reports describing in terms akin to "chemical castration".
Dr Lesley Fallowfield, who led the study, said the study results would be reassuring for these women.
'Good news'
"This is good news for women at high risk of breast cancer who are considering using tamoxifen.
"Much publicity has been generated by various groups who believe that the anti-oestrogenic effects of tamoxifen can be damaging to a woman's health.
"We should certainly never underestimate the effect of menopausal symptoms on a patient's quality of life, but our results are encouraging."
A spokesman for the Cancer Research Campaign said that while the study was reassuring, some women were still experiencing more extreme symptoms following tamoxifen treatment.
She said: "It is definitely comforting if you've a high risk factor of breast cancer."