IntroductionProvidence has ordered nature in such a manner that greater environmental disturbances occur with lesser frequency than disturbances of lesser significance. Storms rage in the sea, but very seldom do the waves trespass the boundary of the shore; tremors are common, yet it is rare for a city to be shaken by earthquakes; and we experience economic recessions far more often than economic depressions. This is a most fortuitous arrangement, as all living systems, including organizations, would otherwise find it very difficult to adapt and be viable.Notwithstanding, smaller disturbances also present their own challenge. Though they are of lesser consequence to organizations, their frequent appearances mean that the interval between one disturbance and the next leaves very little time for a system to respond and adapt. If the response time is greater than the interval, then it is best for the system to ignore these disturbances. This means, however, that the system will have to live with a degree of uncertainty, and, moreover, this uncertainty will be transmitted to other interconnected systems. Therefore, it is necessary that the selection of changes to be ignored follow some precise criteria that rninimizes the uncertainty in the systems. This is the function of cybernetic filters. Filters are of great importance to Management Information Systems (MIS), for they can decide which information should be passed on to each level of management and which should not. In this manner they can save a significant amount of managerial time that would otherwise be spent in responding to disturbances that are beyond the possibility of regulation. The following discussion will not centre so much on the filtering techniques available (for these see [1,2]), but will examine two types of filters that operate on the basis of Ashby's law of requisite variety, and that can be incorporated into a management information system to save ineffectual managerial activity and augment systemic viability. The analysis will draw some principles that indicate how the design of filters, management information systems and organizations ought to be harmonized so that organizations can respond effectively to the various environmental disturbances.