Abstract All business organizations in all countries and at all times suffer insider-crimes in general. The insider criminal accounts are difficult to detect because most are planned in details, some take advantage of existing security laxes and others due to opportunity. Crime Opportunity Theory (COT) is the crux of the study. A criminal is attracted to an object of value when there are no persons or equipment to guard it. An insider crime is a motivation of indication of failure on the part of management to adequately engage security at the business place. Expositive method was adopted for the study, with the aim as a review and compilation of security measures at reducing/preventing crimes in business organizations. The study proves that, an insider crime exists at every level of the business organization, from management to junior workers, from production, distribution chain and marketing sub-units. The means to insider crime is opportunity of free access to business premises, information, persons. It is recommended that, since insider security is relative to the business organization, products and services, management factors and polices, environment, number of employees and management styles, effective communication, team building, reporting system and punishment will help reduce operations. Keywords: Insider, Crimes, Business organization, Security