The present invention relates to a cosmetic or dermatological composition comprising, in a physiologically acceptable support: a) at least one oily phase and b) at least one merocyanine compound of formula (1) defined hereinbelow and c) at least one organic UVB-screening agent chosen from: v) a liquid lipophilic organic UVB-screening agent vi) a hydrophilic organic UVB-screening agent vii) a triazine UVB-screening agent and viii) mixtures thereof； and d) at least one organic UVA-screening agent other than the said merocyanine compound； when the said UVB-screening agent is liquid and lipophilic, the said composition contains less than 2% by weight of cyclohexasiloxane relative to the total weight of the composition. Another subject of the present invention consists of a non-therapeutic cosmetic process for caring for and/or making up a keratin material, comprising the application, to the surface of the said keratin material, of at least one composition according to the invention as defined above. The invention also relates to a non-therapeutic cosmetic process for limiting the darkening of the skin and/or improving the colour and/or uniformity of the complexion, comprising the application, to the surface of the keratin material, of at least one composition as defined previously. The invention also relates to a non-therapeutic cosmetic process for preventing and/or treating the signs of ageing of a keratin material, comprising the application, to the surface of the keratin material, of at least one composition as defined previously.La présente invention concerne une composition cosmétique ou dermatologique comprenant, dans un support physiologiquement acceptable : a) au moins une phase huileuse et b) au moins un composé de mérocyanine de formule (1) définie dans la description et c) au moins un agent anti-UVB organique choisi parmi : v) un agent anti-UVB organique lipophile liquide, vi) un agent anti-UVB organique lipophile, vii) un agent anti-UVB triazine et viii) le
