This is a phase 3b, multicenter, randomized, double-blind, 2-period, 2-sequence crossover study in adults with RA or PsA who are naive to etanercept. The study will evaluate injection site pain associated with the commercial formulation of etanercept and the new formulation of etanercept immediately after injection of each formulation.The study will consist of a screening period of up to 14 days, a 2 week treatment period with a 30 day post treatment safety follow-up. Each dose will follow the recommended label dosing for adults with RA and PsA: 50 mg weekly (scheduled approximately 7 days apart).