Employing a technique associated with optimization problems, a minimum sensitivity solution is obtained for a third-order active filter containing a current conveyor. This solution is given in terms of the time constants for the circuit. Further investigation yields a solution in terms of the resistors and capacitors which, as well as being one of minimum sensitivity, is such that the resistor sum and spread and capacitor sum and spread are all small. Similar results are presented for a third-order active filter containing a controlled source.