The study sought to answer the following questions: what is the profile of the respondents in terms of age, sex, civil status, socio economic status, length of stay in prison, number of time being imprisoned, and crime allegedly committed; Role of Penalty to the Deterrence of Criminality in Terms of Gravity; Role of Penalty to the Deterrence of Criminality in Terms of Extent of Implementation; Is there a significant relationship on the profile of the respondents and their assessment on the role of penalty to the deterrence of criminality?; Is there a significant difference on the assessment of the respondents on the role of penalty to the deterrence of criminality? ; How may the findings be utilized to deter criminality? The researcher used descriptive method of research and employed a purposive sampling. The research questionnaire was administered to the inmates in three city jails in Batangas Province. The population of the study was from 55 inmates in Batangas City Jail, composed of 45 males and 10 females; 67 inmates from Lipa City Jail which was composed of 56 males and 11 females; and 31 inmates from Tanauan City Jail which was composed of 26 males and 5 females. The statistical treatment used was ranking, weighted mean and correlated T-test. Base on the findings, there is a high possibility of doing well if committing crimes has a higher punishment. The citizens will not be afraid to violate the law if the punishment is not something to be afraid of. If the government will issue corporal punishments forces, petty or not, the people will learn not to commit repeated crimes. One of the problems in our judicial system is the slow action in pursuing truth, justice and giving off sentences for the crimes committed which proved to be very essential in the prevention of the commission of crime and further aggravate by belief that there were people who were the victims of the miscarriage of justice or wrongful conviction. Furthermore, the researchers recommended, the Executive branch of the government should recommend to Supreme Court to create more courts and to appoint new judges to hasten the process of trial and the administration of justice. The Correctional Institution should formulate rehabilitation programs intended to prevent repetition of crimes. The Philippine National Police should exert effort in gathering of evidence for the trial and conviction of drug accused in violation of RA 9165 (Comprehensive Dangerous Drugs Act of 2002) and other offenses. The Executive branch of the government should recommend to the legislative branch to propose laws that intend to increase the severity of penalty to deter violations of mostly committed crimes and coordinate with judicial branch for its strict implementation. The Legislative branch of government must seek to update laws as needed, and the judicial branch has to interpret the laws based on evidence presented by both parties. The researcher also recommended the Executive branch should recommend to the legislative branch to enact laws that will reform the judicial branch and the criminal justice system, as a whole.