This Doctoral thesis entitled the Constitutionality of Employers' Investigative Procedures and Disciplinary Hearing Processes with Specific Reference to Dismissal of Employees on the Basis of Criminal Misconducts in South Africa, focusses on individual labour law principles of fair labour practices entrenched in section 23(1) of the Constitution. The thesis deals with fairness in situation where an employee who is suspected of committing a criminal act is investigated and subsequently goes through a disciplinary hearing for dismissal. It determines the extent to which an employee’s criminal guilt is decided before dismissal. As such, the thesis is based upon South African judicial interpretation of the right to fair dismissal. In the process the thesis examines the application of principles informing the employer’s duty to provide fair reason concerning the dismissal of employees criminal suspects. In examining if employers observe constitutional transformative objective when conducting criminal investigations and disciplinary hearings - the thesis reviews the extent to which the employer respects constitutional rationales of equity based on the principles of natural justice. These natural justice principles are the basis upon which section 23(1) fairness is founded. Section 23 (1) is implemented through the LRA provisions. The thesis then concludes that, only one principle of natural justice - audi alteram partem is respected within employer flexibility-based fairness while the other principle - nemo judex in propria sua causa is ignored. It is this denial that causes serious procedural challenges in the quest for equity intended in section 23(1) fair labour practices. It is upon these foundational equity concerns that this thesis opposes the flexibility in employer’s criminal investigations and disciplinary hearing processes entrenched in item 4 (1) of Schedule 8 of the LRA fair procedure for dismissal of employees suspected of criminal acts. The thesis interlinks labour law and criminal law to advocate for the missing constitutionally justiciable fairness for employees who have committed criminal misconducts. It argues that the current judicial interpretation of labour law fairness is based upon the principle of flexibility underlying dismissals, asserting that fairness based on flexibility breeds informal procedural processes which exempt employers from observing crucial constitutional fairness principles expressed through proportionality-based prescripts. The thesis concludes that the practice of including the right against self-incrimination in employment law, done in other common law countries be introduced into the South African labour law through section 39 of the Constitution so that the identified procedural challenges are regulated. / Mercantile Law / LL.D.