The Criminal Justice in Zanzibar is regulated by the Zanzibar Constitution of 1984 and several pieces of legislation including the Criminal Procedure Act No.7 of 2018. The law and practice on forensic evidence in the administration of criminal justice in Zanzibar originated from the criminal cases which relate to offences connecting with forensic evidence. In most cases results seems be negative. The study aimed at examining where the problem is between law and practice. The study used documentary review and interviews in data collection methods. The study has found that there are problems in both law and practice. The Evidence Act of Zanzibar of 2016 and the Criminal Procedure Act No 7/2018. recognize the forensic evidence. However, due to unethical behavior and low skills to investigators, prosecutors and adjudicators prevail a negative impact on forensic evidence. Following those findings, several recommendations have been given including amendment of the Evidence Act No.9/2016 to improve definition of the term expert, making clarity in the law on how expertise can be obtained, the value of expert evidence or forensic evidence to be improved and the law to make clear distinction between expert opinion and third party opinion.