The experiment was carried out at the Agronomy Field Laboratory, Sylhet Agricultural University, Sylhet, Bangladesh during January to December 2013. The experimental site was located in Sylhet district which is in the north-east corner of the Bangladesh lying between 23º57′ to 25º13′ north latitude and 90º56′ to 92º21′ east longitude and about 30 m above the sea level. The soil of the experimental field is sandy loam with pH 4.5-5.5, organic matter 1.45%, total nitrogen (N) 0.80%, potassium (K) was 0.07 m mol100g-1of soil, phosphorus (P)was 25 μgg-1 of soil and sulphar (S) was 10 μgg-1 of soil and belongs to the Khadimnagar soil series under Agro-Ecological Zone of Eastern Surma-Kushiyara Floodplain (AEZ 20). The experiment comprised of two varieties of mungbean viz., BARI Mung-5 and BARI Mung-6; and twelve different sowing times starting from January to December 2013considered as treatments. Over all treatments combinations were S1×V1, S1×V2, S2×V1, S2×V2, S3×V1, S3×V2, S4×V1, S4×V2, S5×V1, S5×V2, S6×V1, S6×V2, S7×V1, S7×V2, S8×V1, S8×V2, S9×V1, S9×V2, S10×V1, S10×V2, S11×V1, S11×V2, S12×V1, S12×V2. But sowing can’t be done in the month of January, February, November and December because of unavailability of residual soil moisture and unavailability of rainfall on the other hand, experimental plots were damaged dueto excessive rainfall in the month of May, August and October). So only five sowing dates were considering among all the treatments and data were analyzed. Seeds were collected from Bangladesh Agricultural Research Institute (BARI), Gazipur. The experiment was laid out in RCB (Randomized Completely Block) design with three replications. The unit plot size was 10 m2 (4 m × 2.5 m). The distance between the replication was 1.0 m and the adjacent unit plot was 0.5 m. For each of the sowing date six plots were ploughed and land was well prepared before each sowing. The experimental plots were fertilized at the rate of 18, 32 and 21 kg ha-1 of N, P and K, respectively for each sowing time. The whole amount of Nitrogen, Phosphorus and Potash fertilizers were applied as basal dose during final land preparation. Seeds were sown in continuous line seeding latter on try to maintain plant spacing of 30 cm × 10 cm but due to disease, pest incidence plant population was varied. Seeds were sown in specific time and combinations of treatments were allocated randomly to the plots in each replication. Weeding was done at 19-20 days after sowing (DAS). The crop was sprayed with Admire 200 SL during the flowering and pod setting stages to save the crops against pod borer (Helionthes sp.) and also sprayed with Bavistin (0.2%) to prevent Cercospora leaf spot. Pods were harvested on an average about 60 days after sowing (DAS) for each of the sowing times and two plucking were done about 10 day’s intervals during harvesting. Five plants from each plot were selected at randomly before harvesting and were uprooted for collection of yield attributes data. After threshing and separation, seeds were dried in the clear sun for consecutive three days to attain a standard moisture level of 9-10%. The following observations were made with regards to different yield contributing characters of the crops. These are number of plants m-2, number of branches plant-1, number of pods plant-1, number of seeds pod-1, pod length (cm), 1000 seed weight (g), grain yield (kg), stover yield (kg), harvest index (%). Harvest index was calculated on the basis of grain and stover yield using the following formula of Gardner et al.(1985). The recorded data were analyzed statistically following the computer package MSTAT Cand means were tested by Duncan’s Multiple Range Test (DMRT).