• Considering the rate of Exclusive Breast Feeding (EBF)43% in the control clusters, Bangladesh Demographic Health Survey (BDHS) 2007 and the expected rate of EBF about 63% i.e. an increase of 20% in the intervention group the required sample size will be 92.4 for each group and using formula; n= P1(100-p1) + P2 (100-p2)/(P2-P1)2 x 7.9 Taking 95 (round up the figure) and multiplying by 4 to reduce the cluster effect the sample size become 380. Calculating a 20% drop out, out migration the required sample size comes to 456 in each group to have a 0.05 significance and with a power of 0.80.