Abstract. Linear Ordering Problem (LOP) is a well know NP-hard combinatorial optimization problem attractive for its complexity, rich library of test data, and variety of real world applications. This study investigates the bio-inspired Artificial Immune Systems (AIS) as a pure metaheuristic soft computing solver of the LOP. The well known LOP library LOLIB was used to compare the results obtained by AIS and other pure soft computing metaheuristics.