The thesis purpose is to analyze Thailand laws regulating controlled delivery measure to drug cases in which criminals have transformed to complicated international organized crime. As a result, it is very difficult to detect who are involved with the case such as mafia, Transnational Criminal Organization or else. The worse case is they will disguise their illegally obtained funds so that they seem legal which is a significant obstacle for investigators to do their job. The writer has also studied controlled delivery measure under the international level, related provisions of international treaties, and related internal laws to see if laws are potentially competent with controlled delivery in Thailand Upon the study, the writer has learned that there are 2 laws mainly related to controlled delivery measure which are Narcotics act B.C. 2522 as amended by the Narcotics act (no 5) B.C. 2545 and Act on procedure of narcotic case B.C. 2550. These two laws, in the writer's view, have some flaws about their proceedings, their steps of action, and controlling & monitoring on the measure. Therefore, the writer would like to offer some solutions as follows:1. Thai laws should have controlled delivery measure for both the replacement of substance and the pure substance.2. There should be an amendment of rule under article 15 of Narcotics act B.C. 2522 as amended by the Narcotics act (no 5) B.C. 2545 to cover controlled delivery for domestic drug case investigation as well.3. To regulate the rule under article 8 the last paragraph of Act on procedure of narcotic case B.C. 2550, the rule should be well-defined of such guidelines, methods, and procedures of controlled delivery as an officer election, asking for permission, officer scope of action, retention of property in dispute, and authorizing the measure etc. 4. As to international drug controlled delivery regime, there should be proper principles regarding government officers having to take actions under either Narcotics act B.C. 2522 as amended by the Narcotics act (no 5) B.C. 2545 or Act on procedure of narcotic case B.C. 2550. 5. In order to authorize controlled delivery measure, the balance of controlling procedures and the convenience of officers to carry their work should be taken into consideration. The officers should have given the power of making such decisions. Unnecessary procedures should be deducted. Confidentiality of proceedings is essential in some cases. Electing officers should be run carefully. Furthermore, after getting all procedures done, the officer should report to their boss every detail in order for to scrutinize the measure.