Coordinated activity of the actin cytoskeleton and microtubules is critically important for a variety of basic cellular functions, including cell motility, adhesion, polarization and division. The molecular mechanisms underlying this coordination are, however, poorly understood. Here, I discuss actin-microtubule crosstalk mediated by proteins of the formin family. Formins bind actin and strongly facilitate nucleation and elongation of actin filaments. In the course of filament elongation, formin dimers function as “processive caps”, which remain associated with the growing filament plus-ends thereby permitting, and in some cases facilitating, incorporation of the new actin subunits. In particular, our theoretical study showed that formin-mediated actin elongation can be facilitated by the application of pulling force to the formin cap. In addition to this well-documented effect on actin, changes in formin activity in cells lead to specific alterations in microtubule dynamics. We have shown that constitutively active formin Dia1 triggers a decrease in microtubule growth and shrinking velocities; this decrease is not accompanied by any changes in probabilities of microtubule “catastrophe” and “rescue” events. Consistent with these results, knockdown of Dia1 leads to an increase in microtubule growth velocity. The effect of Dia1 on microtubule dynamics is actin-dependent and can be abolished by the inhibitors of actin polymerization, cytochalasin D or latrunculin B. In addition, active formins including Dia1 and Fmn-1 preserve a dense microtubule array in enucleated cell fragments (cytoplasts) lacking a centrosome, most probably, by stabilizing microtubule minus-ends. We hypothesize that Dia1 and other formins may create 'flexi leash' type connections between dynamic microtubule ends and actin filaments. The possible mechanisms of these effects based on formin interactions with proteins regulating microtubule functions, such as tubulin deacetylase HDAC6 and the dynactin complex will be discussed. Finally, I will describe a possible role of formin-mediated actin-microtubule interactions in cell-cell and cell-matrix adhesion.