Cell adhesion and proliferation on poly(D,L-lactic acid) (P(DL)LA) tissue-engineering scaffolds is low. This is generally regarded to be due to the surface chemistry of the P(DL)LA polymer, although topographic features often worsen the situation. This study reports for the first time successful deposition of a plasma polymer throughout the porous network of a three-dimensional scaffold. This allylamine plasma deposit was used to improve cell adhesion on the PDLLA surface. X-ray photoelectron spectroscopy (XPS) analysis of sectioned scaffolds was used to demonstrate the penetration of nitrogen species to the inner surfaces and to compare the virgin P(DL)LA scaffold and the plasma polymer coated P(DL)LA scaffold with plasma-grafted allylamine. The nitrogen concentration at the exterior and interior scaffold surfaces was greater for the plasma deposits than for the grafted surfaces, and the chemical state of the incorporated surface nitrogen using the two methods was found to be different. Evaluation in vitro was carried out by studying 3T3 fibroblast attachment, morphology, and metabolic activity on the scaffolds. Cell activity and attachment was found to be greater for the plasma deposits than the plasma-grafted P(DL)LA scaffolds, and both were greater than for the virgin P(DL)LA scaffolds. It is concluded that plasma deposition is a viable method of increasing cell attachment throughout porous P(DL)LA scaffolds without changing the bulk characteristics of the polymer.