Investigation was aimed to choose the optimal freezing technique and to estimate the effect of addition of dimer of lysozyme on the quality of deep frozen boar spermatozoa. The investigations were carried out on 115 ejaculates. Semen was frozen in large, flat straws and pellets. The highest quality of boar semen after thawing was observed in semen processed and frozen according to Pursel and Park method in the form of pellets and flat straws. Significantly higher motility and intact acrosomes was observed in the samples where 4 and 6 μg dimer of lysozyme was added.

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