The Master's thesis aims to introduce the criminal liability of engineer responsible for construction works; A comparison study between the Omani, Egyptian and UAE law. the researcher determined the responsibility of Engineer for not to taken into account technical procedures in the design, implementation and the supervision of construction, as well as determining his liability under the general rules related to the construction work like involuntary manslaughter, and involuntary abuse and his responsibility for the money crimes like fraud and breach of trust. The thesis also discusses the circumactances where criminal responsibility of the Engineer is proved not valid like limitation of liability, force majeure and the mistakes of employer and others. The main findings of the study: 1) The work of designs is one of the main duties of the engineer so he must be committed to the technical rules and standardspecifications that must be known by all specialized people in this field, and he also has to adhere to laws, regulations and decrees governing the operations of construction to avoid mistake. 2) If the work of the engineer is restricted on the design without the supervision of construction, he will be only responsible of the design flaws. 3) Some of the duties of the engineer are: supervising the implementation, reviewing the designs, checking the status of the soil, confirming that work accomplished matches with the designs, and checking the validity of materials used and their compliance with the established standards. 4) If the work of the designing engineer included the supervision of construction, he would be jointly liable with the contractor about the flaws of the construction. 5) the engineer may questioned in accordance with the general rules about the crimes that occur to persons as the crimes of involuntary manslaughter, involuntary abuse as well as responsibility for the crimes related to the money like fraud and breach of trust. 6) The responsibility of the Engineer may elapse from penal accountability under the general rules that have been stipulated in Omani Code of Criminal Procedure such as Prescription or in the Omani Penal Code such as force majeure and the employer and others intervention.