B-triggers at ATLAS and CMS

This paper describes the $B$-physics trigger strategies for the ATLAS and CMS experiments. The LHC will produce $B$ events at an unprecedented rate allowing the possibility to study rare decays. Due to the high event rate at the LHC the trigger systems are required to be very selective, reducing the rate by about six orders of magnitude for recording. The B-trigger must be able to reject non-B background (only about one collision in a hundred will produce a {\bbbar} pair) and select the B-decay channels of specific interest (often with low branching ratios). In addition the $B$-trigger must be flexible enough to cope with increasing luminosity during the period of LHC running. The different strategies used to achieve this flexibility are discussed in this paper.