The stability of marine fuels could be affected by sediments and sludge, which may block filters and lines in the feeding pipes and engines. For these reasons, marine fuels have to meet the stability parameters, respectively the content of sediment after aging according to the ISO 8217. The stability as well as compatibility of marine fuels is a very important and frequently discussed parameter, especially with the expected change in the sulphur content (sulphur cap) after 2020, when marine fuels will be produced by the blending of different stocks. A comparison of two alternative methods for the evaluation of marine fuel stability was done. These methods were based on the Spot test according to ASTM D 4740. In the first method, the spot was visualized, modified by software and converted into RGB histograms. In the second case, the fluorescence self-quenching was used for evaluation of the stability and the thin layer of the diluted analytical sample was screened using near ultraviolet light. The comparison and relationships of the presented methods as well as conventional and other widely used methods or qualitative parameters are discussed.