MOTIVATION: TTA Lynx is a web-based service for finding, assessing and comparing coding sequences that contain TTA codons. This codon is most notable for being a regulatory switch that governs different aspects of the physiology of several GC-rich, Gram-positive bacteria belonging to genus Streptomyces, prolific producers of clinically important natural products. The ever-increasing pace of genome sequencing is creating a huge volume of data that could be utilized to improve our understanding of rare codons in actinomycete biology (and other biological systems.) The service described here is designed to facilitate analysis of TTA-containing genes and to assess the importance of TTA-mediated regulation in an organism of interest. This service and its database of organisms with well-known or hypothetical TTA-based regulation provides an opportunity for the identification of such regulation on a genome-wide scale. AVAILABILITY: http://ttalynx.bio.lnu.edu.ua.