We discuss challenges arising from the quest for high average powers from p
assively mode-locked diode-pumped lasers. The recently obtained detailed un
derstanding of Q-switching instabilities in passively mode-locked lasers tu
rns out to be a crucial element on the way towards higher powers. We give a
n overview on results achieved with Nd:YAG (10.7 W, 16 ps and 27 W, 19 ps),
Yb:YAG (8.1 W, 2.2 ps and 16 W, 0.7 ps) and Nd:glass (1.4 W, 275 fs).