As drug testing has become increasingly used to maximize corporate profits by minimizing the economic impact of employee substance abuse, numerous arguments have been advanced which draw the ethical justification for such testing into question, including the position that testing amounts to a violation of employee privacy by attempting to regulate an employee's behavior in her own home, outside the employer's legitimate sphere of control. This article first proposes that an employee's right to privacy is violated when personal information is (...) collected or used by the employer in a way which is irrelevant to the terms of employment. This article then argues that drug testing is relevant and therefore ethically justified within the terms of the employment agreement, and therefore does not amount to a violation of an employee's right to privacy. Arguments to the contrary, including the aforementioned appeal to the employer's limited sphere of control, do not account for reasonable constraints on employee privacy which are intrinsic to the demands of the workplace and implicit in the terms of the employment contract. (shrink)