Previous studies have demonstrated an empirical relationship between accumulated R&D expenditures and total factor productivity (TFP), and have shown that the benefits of R&D can spill across countries through trade. This paper extends these analyses to a sample of 15 OECD countries and six Asian countries, Chinese Taipei, India, Indonesia, Korea, Singapore and Thailand. An empirical model is estimated which relates TFP to domestic and foreign R&D activity, TFP catch-up and business cycle variables. Model estimates show that TFP and domestic R&D capital are positively related, and that domestic R&D has a relatively large impact on TFP growth in the NICs and LICs. Country-specific international R&D spillover elasticities are of mixed sign, and no apparent pattern by country group is evident. While this result does not change the earlier qualitative conclusions, it suggests that estimates of sample average R&D spillover elasticities should be cautiously interpreted.