The funnel-web spider, Agelena labyrinthica, is widely distributed throughout Turkey. The objective of the present study was to describe the histological and functional fine structure of A. labyrinthica's venom gland by using light microscope, scanning (SEM) and transmission electron microscope (TEM). We have also preliminarily analyzed venom components by SDS-PAGE. Each venom gland has surrounded by a thin adventitia and gross striated muscular bundles. Basal lamina underlies between muscular bundles and the inner glandular epithelium, and ties up them each other. The striated muscular bundles spirally covered venom gland has been observed by SEM. Intricate relations formed between motor neuron axons and the muscle fibers have been revealed by TEM. The secretory epithelium, which made up of simple columnar cells, formed the secretory region of the venom gland. The secretory surface of the gland was increased by a sort of fringes extended from basal membrane into the gland lumen. The epithelial cells have many rough endoplasmic reticulum, mitochondria and different size and shape of secretory granules. These granules have been accumulated in apical portion of the secretory cells. After the gland is emptied, the apical portions of secretory cells deteriorate and the basal epithelial cells regenerate the columnar cells. The analysis of A. labyrinthica venom, which was achieved by SDS-PAGE showed that there have been at least seven components ranging from 10 to 40 kDa molecular weight. (C) 2005 Elsevier Ltd. All rights reserved.