We propose nonlinear control using immune-algorithm-based fuzzy logic. Nonlinear dynamic systems include chemical and biomedical processes and mainsteam temperature control at thermal power plants. PID controllers are conventionally used to operate these systems, but using these requires experience, often based on trial and error to tune them. We use an inverted pendulum control problem to demonstrate the efficiency of the proposed method and define the relationship of state variables using immune fuzzy logic. Simulation results show the effectiveness of the tuning algorithm, but study experiments are needed before actual application.