Photodynamic therapy (PDT) is a contemporary approach to cancer treatment that relies on interaction of light of a specified wavelength with a photosensitizer molecule that has the ability to excite molecular oxygen to a higher energy state. During that process, molecular oxygen receives energy from the photosensitizer in its excited triplet state, thus becoming highly reactive singlet oxygen. The therapeutic effect is achieved by cytotoxic activity of singlet oxygen targeted at tumor tissue. Reactive oxygen species such as singlet oxygen are capable of damaging proteins, lipids, nucleic acids and other cellular componets at the site of impact. By modifying the properties of the photosensitizer one can improve the effectiveness of PDT. Due to ther characteristic absorption and emission spectra, porphyrins are particularly interesting candidates for usage as photosensitizer molecules. Choosing a porphyrin that is a potential candidate for PDT requires development of reliable methods for measuring singlet oxygen production. In this work, singlet oxygen production by two N-methylated and two N-oxidated porphyrins in four solvents was measured indirectly using photodegradation method. The aforementioned method relies on measuring the decrease of fluorescence emission by control dye, in this case DPBF, in the presence of singlet oxygen. The advantage of this method is simple application and commercial availability, although it has to be noted that the result vastly depends on conditions during experiment. Solubility of porphyrins in various solvents was compared in regards to their N-substituent as well as the effect of solubility of N-substituted porphyrins on singlet oxygen production. It was found that all of the examined porphyrins have significant singlet oxygen production at least in some of the solvents. Also, it was shown that singlet oxygen production depends on solubility of the porphyrin in a given solvent.