APLAS 2005 was the Asian Symposium on Programming Languages and S- tems, held in Tsukuba, Japan in November 2-5, 2005. It was the latest event in the series of annual meetings started in 2000 by Asian researchers in the ?eld of programming languages and systems. The ?rst three were organized as wo- shops, and were held in Singapore(2000), Daejeon (2001), and Shanghai (2002). Theenthusiasmthere, encouragedbytherichproductionoforiginalresearch- pers, and the support of the internationalresearchcommunities in programming languagesandsystems, ledtothe?rstAPLASasasymposiuminBeijing(2003), followed by the one in Taipei (2004). APLAS 2005 was the third symposium in the series. In the past ?ve yearswe havewitnessed the growing role of APLAS as one of thekeyresearchcommunitiesoftheworld.ThisisnotonlybecauseAsia andthe Paci?c Rim is a fast-growing region of IT industries, but because it is a region of highly cultivated human resources. We are con?dent that forums like APLAS will further engender interaction among Asian researchers and with the rest of the world. As for the scope of APLAS, from the very beginning we have been striving to achieve the cross-fertilization of theories and system developments of p- gramming and programming languages. The papers selected for the publication of this volume of the proceedings are the evidence of our e?orts. We are very grateful to the contributors of the submitted papers; they came not only from Asia and Australia but from Europe and North America.