This mini-review summarizes literature and original data about the role of microtubules in interphase animal cells. Recent data have shown that functioning of microtubules is essential for such diverse phenomena as directional cell movements, distribution of organelles in the cytoplasm, and neuronal memory in the central nervous system. It is suggested that microtubules can act as an important regulatory system in eukaryotic cells. Possible mechanisms of these functions are discussed.