Анотация: The aim of the present investigation was to determine the localization, histochemical reactivity and the dimensions of connective tissue fibres in the wall of canine paranal sinus (PS) as well as to determine the dimensions of elastic and collagen fibres. The stroma was composed mainly by collagen fibres (CF). The thicker CF were situated in the subglandular connective tissue between the apocrine glands and sinus musculature (SGS) whereas those located in the connective tissue between the sinus epithelium and apocrine glands (SES) were statistically significantly thinner (p<0.01). CF with a various thickness were observed, that decreased in the direction of the epimysium of the external anal sphincter (ES) to the endomysium. The reticular fibres (RF) were assembled immediately under the multilayer squamous sinus epithelium. They were located both around the apocrine tubules and among the tubules. RF embedded sebaceous glands, skeletal muscle cells and smooth muscle cells. Elastic fibres (AF) located in SGC and ICT were thicker and longer than those in SEC. The AF in SES were thinner and shorter compared to those in SGS. Histochemically, a various degree of reactivity of CF and EF in the wall of the paranal sinus, was observed