The evolutionarily conserved Hippo signaling pathway plays an important role in regulating normal development as well as tumorigenesis in animals. How this growth-inhibitory signaling is maintained at an appropriate level through feedback mechanisms is less understood. In this report, we show that bantam microRNA functions to increase the level of the Mob as tumor suppressor protein Mats, a core component of the Hippo pathway, but does not regulate mats at the transcript level. Genetic analysis also supports that bantam plays a positive role in regulating mats function for tissue growth control. Our data support a model that bantam up-regulates Mats expression through an unidentified factor that may control Mats stability. (c) 2013 Elsevier Inc. All rights reserved.