In the growing optical communication industry, one of the hottest segment is the emergence of Small Form Factor (SFF) optical system. Under the key words such as high port density, low cost and utilities, it has attractive feature to be expected the future standard and strong driving force for additional growth not only in data communication but also tele communication industry. Now several types of SFF connectors are introduced, they have their own unique feature.On the other hand, the emergence of transceiver plays another important roll so that SFF could be spread broadly and widely accepted into the market, as well. Now here's another thing to be considered; the interoperability. As was the case of SC duplex connector; which is current industry de-facto standard, we learned that it is quite important to determine common electric interface like pin assignment and its definition as well as physical size; so called "Common Footprint." Because it has prevented any confusion and even brought the motivation in the market. From this viewpoint, several transciever companies reached the agreement and signed up the mutual MSA (MultiSource Agreement) regardless which SFF connector was chosen.Eigure 1 . Externalview of Sumitorno SFF transceive r We; Sumitomo Electric Industries, are the first company who has introduced transfer molding technology in high performance 1310nm LED/LD based optical modules and has many experience with developing this technology for the various opto-electronic products; with which the productivity and reliability have been significantly improved [1][2]. Our latest achievement in molding technology such as HOElC (Hybrid Opto-Electronics Integrated Circuit) and SMD (molded Surface Mountable optical Device) is proven to be the most economical and appropriate method for small packaging. Recently, we're successful for developing our SFF transceiver with combinig those technologies. In this paper, we mainly present how our transfer molding process has been evolved to the most suitable technology for small packaging. First, our background of optical module packaging technology is reviewed.Then, basic packaging concept and the requirement for SFF are discussed.