The incidence of skin cancer is increasing by epidemic proportions. Basal cell cancer remains the most common skin neoplasm, and simple excision is generally curative. On the other hand, aggressive local growth and metastasis are common features of malignant melanoma, which accounts for 75 percent of all deaths associated with skin cancer. In Croatia only, more than 20.000 new cases of skin cancer has been diagnosed in 2008 of which melanoma 286 new cases and 118 yearly deaths in men, and 275 new cases and 79 deaths in women population. The back sides in men and women, as well as the lower limbs in women, are the most common site for melanomas. The primary cause of skin cancer is believed to be a long exposure to solar ultraviolet (UV) radiation crossed with the amount of skin pigmentation in the population. There are indications that other parts of solar spectrum (e.g. blue light) might also have effects on skin and eyes. Most people think all clothing will protect them, but thats not the case. UV clothing can show UV protection, but in the most cases it does not provide full sun screening properties. UV protection ability highly depends on large number of factors such are type of fi ber, fabric surface and construction, type and concentration of dyestuff, fl uorescent whitening agent (FWA), UV-B protective agents, as well as nanoparticles, if applied. For that reason, jeans and tightly woven fabrics offer a very good level of protection. However, on a hot summer day, those arent the kinds of clothing people usually reach for. More often, when they are on the beach, they wear T-shirt, as well during the swimming in the sea, thinking that it will protect them. Therefore, in this paper the discrepancy of UV protection in wet state was researched. For the purpose, FWA and UV absorber were applied in wide concentration range to white cotton knit fabrics commonly used for T-shirts. Afterwards, the discrepancy in whiteness and UV protection was research in distilled water as well as Adriatic Sea water.