beta-mannanases can degrade galactomannans to mannose and it has been used in various application areas. The aim of this study was to produce the beta-mannanase from carob pod extract including different nitrogen sources. The best operation values for fermentation were determined to be 8% initial sugar concentration with 0.5% yeast extract, 100 r.p.m., and 7% inoculation rate, which yielded the maximum beta-mannanase activity as 423.60 U ml(-1). Effects of nitrogen sources on beta-mannanase activity were also studied and it reached 695.6 U ml(-1) by using 0.5% of ammonium nitrate as the nitrogen source at the determined optimum conditions. Results also showed that meat bone meal and soybean meal could be used as cost effective nitrogen sources based on achieved beta-mannanase activity.