A study was conducted to evaluate the effectiveness of computer assisted teaching program on knowledge regarding menstrual blood banking among 3rd year basic B.Sc. nursing students at selected nursing colleges, Hassan. 50 students were selected by non probability purposive sampling technique. The knowledge was assessed by using structured knowledge questionnaire. The study results revealed that  most of the respondents 48(96%) had inadequate knowledge, 2 (4%) of the respondents had moderate knowledge and none of them had adequate knowledge during pre-test.  After computer assisted teaching program 26(52%) of the respondents had moderate knowledge,  24(48%) of them had adequate knowledge and none of them had inadequate knowledge. The calculated paired ‘t’ test value of 22.5* is greater than the table value at 0.05 level of significance, which indicates that there is a significance difference between mean pre-test and post-test knowledge  scores of whole tests of respondents. It is concluded that CATP was effective in increasing knowledge of 3rd year B. Sc. students regarding menstrual blood banking.