During their rst observational run, the two Advanced LIGO detectors attained an unprecedented sensitivity, resulting in the rst direct detections of gravitational-wave signals produced by stellarmass binary black hole systems. This paper reports on an all-sky search for gravitational waves (GWs) from merging intermediate mass black hole binaries (IMBHBs). The combined results from two independent search techniques were used in this study: the rst employs a matched- lter algorithm that uses a bank of lters covering the GW signal parameter space, while the second is a generic search for GW transients (bursts). No GWs from IMBHBs were detected; therefore, we constrain the rate of several classes of IMBHB mergers. The most stringent limit is obtained for black holes of individual mass 100M , with spins aligned with the binary orbital angular momentum. For such systems, the merger rate is constrained to be less than 0:93 Gpc3 yr 1 in comoving units at the 90\% con dence level, an improvement of nearly two orders of magnitude over previous upper limits.