The aim of this study was to screening of some elements in different silk cocoon varieties. The varieties of silk were Thai silk (yellow color; Samrong, Nangtui, Nanglai, Huafai, Nangnoi, Nanglaung, Nangseiw, Surin4, Nongkhai012, Green and Gold colors), wild silk (Eri), Japanese and Chinese silk. The cocoons were collected and subjected for investigation of element composition by using SEM/EDX technique. The results found that the elements were arranged in following order of C>O>Ca>Si>Cl>S>Mg for inner surfaces of silk cocoons. For the outer surfaces, all elements were distributed in all Thai strain which slightly differed for each silk strain. Among them, C and O were found in high percentage in all silk cocoons both inner and outer surfaces. Japanese showed higher element than Chinese, but lower than Thai silk varieties. The result indicated that elements may be involved the silk spinning process of silk fiber to promote β-sheet structure. © 2010 Asian Network for Scientific Information.