At present great experience has been accumulated by many countries in designing photobioreactors for microalgal cultivation. This work analyzes the available photobioreactors of different designs. The constructions of bioreactors, such as thin-layer bioreactors, film bioreactors, bioreactors for submerged cultivation, cavity bioreactors, are described in detail. The analysis of the existing designs of bioreactors, done with criteria of the CELSS in mind, showed the development of cavity bioreactors to hold the greatest promise. The photobioreactors with built-in light conductors, developed by Japanese researchers, also hold much promise. Further work at optimizing the cultivation process in bioreactors will considerably increase their efficiency and result in passing on to the next stage - development and production of photobioreactors for space conditions.