Because microscopical identification and counting is vital in most aerobiological studies, pollen and spores are usually collected on some adhesive. The adhesives should not be water-soluble. For optically best results water-soluble mounting media with refractive indices about 1.40–1.45 are used. There are compatibility problems between water insoluble adhesives and watery mounting media. The former tend to move to stripes or droplets, distorting the image and moving the spores from their original positions. To solve this problem several adhesives based on silicone oils, silicone greases and vaseline or their mixtures were tested. The usual watery mounting media, glycerine gelatine, gum arabic and polyvinyl alcohol based mixtures were tested for their compatibility with adhesives, optical quality and durability. Most combinations and all those in common use proved to be unsatisfactory. The best adhesive was a mixture of vaseline, silicone oil and paraffin wax. The best mounting medium was composed of polyvinyl alcohol, water, glycerol and lactic acid.