This article describes the fabrication of solid and porous polylactide (PLA)-multiwall carbon nanotube (MWNT) composites prepared using melt blending and subsequent batch processing of porous structures The morphology and thermal, rheological and electrical properties of the PLA-MWNT composites prepared with MWNT concentrations of 0, 0 5, 1, 2, and 5 wt% were characterized The composite structure consisted of identifiable regions of MWNT aggregation and MWNT dispersion Increasing MWNT content was found to increase the thermal stability and crystallization kinetics of PLA The addition of MWNT to PLA significantly increased the melt viscosity and electrical conductivity of the composites Based on rheological and electrical measurements, a continuous MWNT network structure in PLA was found to form when the concentration of MWNT is increased from 0 5 wt% (0 33 vol%) to 1 wt% (0 66 vol%) As many current day applications of polymers and polymer composites require lightweight and low-density materials, porous PLA-MWNT composites were fabricated from a batch porous structure processing technique Porous PLA-MWNT composites containing 2 and 5 wt% MWNT had lower relative densities, which is attributed to the higher viscosity of the composites suppressing collapse of the porous structure during processing POLYM ENG SCI, 51 43-53, 2011 (C) 2010 Society of Plastics Engineers