A Compulsory Research Report Submitted to Mzumbe University – Mbeya Campus College in Partial Fulfillment of the Required of the Award of Bachelor Degree of Laws (LL.B) of Mzumbe University.This study was conducted to assess the effect of donatio mortis causa and Islamic Law was taken as a case study. The research specifically undertaken for the purposes examine the effectiveness of donatio mortis causa basing under Islamic law, to examine the compliance with how donatio mortis causa can be made and to assess the legal consequence for failure to comply with Islamic law and condition of donatio Mortis causa. The research was conducted on a sample of 40 respondents, both Muslim laymen, Advocates and Magistrates. Pwani was taken as research design to represent other Regions in Tanzania due to limitation of time and financial capacity to collect data from other different region. Both primary and secondary data was used to collect data, interview and questionnaire was used as the method to collect primary data whereby a researcher supplied questionnaire paper to respondent for the seek of data and some of the respondent was interviewed by the researcher herself. Finally, the study came with the findings that many of people are not aware on the principle and condition of the donatio Mortis causa especially laymen. Although the majority of Muslim they failed to distinguish between will and Donatio Mortis causa. Islamic law did not direct provide any principle or condition of Donatio Mortis Causa but conditions of donatio mortis are established under common law and it is useful in Tanzania. Researcher has the view that, the law should be amended to meet the society needs and to remove unnecessary contradiction.