The skins have been classified in phototypes according to their resistance in front of the radiations that depend in turn on the pigmentation. Thus, skins fewer pigmented or whiter are recognized to be more sensitive to the radiation, presenting bigger susceptibility to suffer picture-damage that goes from an actinic erythema and cutaneous skin photo aging to the skin cancer that is attributed mainly to the UV rays present in the solar radiation. The photoprotecting capacity of the skin stays during some time after which they can begin to present alterations, that is why is recommended the use of measured external photoprotectors as long sleeve clothes to avoid exhibitions in extreme exposure hours and to use protective or index acquaintance's of protection solar screens identified by numbers, being the adults indicative of a bigger photoprotection. In our study the indexes or times of natural protection (IPN) and the factors of solar protection (SPF) required by individuals with different phototypes were determined, specifically the I (white skin, blond hair and tendency to suffer burns), the II (lightly dark skin, soft suntan and tendency to suffer burns) and the III (tan lightly brown, good skin and it rarely suffers burns). Measurements in 58 healthy voluntary fellows were carried out using the team Sun Protection Diagnostic SP37, with different exposure times and different solar intensities, taking in consideration the altitude and the presence or not of reflections conditions that are provided by the team. Significant differences were obtained (test P < 0,05) in the indexes of natural protection of all the phototypes, when using different solar intensities, in turn the Villasmil, S., Fernandez, C., Calderon, L., Morillo, S. Evaluacion del factor de proteccion solar requerido (SPF) y el tiempo de proteccion natural (IPN) de la piel