Species complex Fusarium sambucinum was frequently isolated from ash stands in Montenegro. Previous researches revealed that it is dangerous pathogen for one-year-old seedlings. The aim of this research was to investigate the influence of temeperature on growth and morphological characteristics of morphotype isolated from one-year-old common ash (Fraxinus excelsior L.) seedlings in Montenegro. Growth of Fusarium sambucinum pure cultures on different temperatures was the fastest on 25°C while the absence of growth occurred on 32.5°C. Cultures on optimum temperature were white reddish, aerial and with a lot hyaline, curved multi septate conidia. This research covers basic ecological and morphological characteristics of Fusarium sambucinum strain responsible for high pathogenicity towards one-year-old common ash seedlings in Montenegro.