Researchers at Harvard Medical School looked at the diets of women when they were aged three to five, using information from their mothers who were asked how often their daughters ate or drank various products.
"These data suggest a possible association between diet before puberty and the subsequent risk of breast cancer," report the researchers in the August issue of International Journal of Cancer.
The scientists said that while eating potatoes themselves was not associated with increased risk, the preparation of chips - frying in fat high in saturated fats and trans-fatty acids - may be of relevance.
By contrast, the study found that regular consumption of whole fat milk each day was linked to a small decrease in breast cancer risk.
The risk of getting breast cancer by the age of 60 is about one in 25. Dr. Karin Michels and colleagues estimated that eating chips just once a week before the age of five would raise that to about one in 20 - an increase in risk of 27 per cent.
However they do warn that "differential recall of preschool diet means their data (30-item food-frequency questionnaire) should be interpreted with caution - the information was dependent on the mother's ability to recall her daughter's diet some 30 or 40 years ago.
In total, the researchers analysed data from 582 women with breast cancer and 1,569 women without the disease in 1993, all who were part of the larger, long running Nurses' Health Studies.
The US has one of the highest incidences of breast cancer in the world, where it accounted for 41,250 deaths in 2002. The American Cancer Society estimates that in 2005 approximately 211,240 women will be diagnosed with the disease.
In Asian countries such as Japan, where the typical diet contains much less fat and more fresh, high-fiber foods, breast cancer rates are much lower.
The researchers warned that further studies are required to evaluate further the link between pre-school diet and breast cancer.