A Pd/P(t-Bu)(3) catalyst system has revealed very high activity and selectivity for the amination of N-(hetero)aryl halides with unprotected piperazine. A wide variety of N-(hetero)arylpiperazines could be prepared using this catalyst. Turnover numbers up to 6400mol/mol have been obtained. (C) 1998 Elsevier Science Ltd. All rights reserved.