We present a search for the technicolor particles ρT and πT in the process pp̄→ρT→WπT at a center of mass energy of √s=1.96TeV. The search uses a data sample corresponding to approximately 1.9fb-1 of integrated luminosity accumulated by the CDF II detector at the Fermilab Tevatron. The event signature we consider is W→ ν and πT→bb̄, bc̄ or bū depending on the πT charge. We select events with a single high-pT electron or muon, large missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with multiple b-tagging algorithms. The observed number of events and the invariant mass distributions are consistent with the standard model background expectations, and we exclude a region at 95% confidence level in the ρT-πT mass plane. As a result, a large fraction of the region m(ρT)=180-250GeV/c2 and m(πT)=95-145GeV/c2 is excluded. © 2010 The American Physical Society.