Objective of this study was to select ectomycorrhizal fungi for black spruce(Picea mariana) inoculation to overcome the growth inhibitory effects of Kalmia angustifolia. Nineteen isolates representing 11 species of ectomycorrhizal fungi were tested for their abilities to grow and form mycorrhizae with black spruce seedlings in the presence of water leachate of leaves of Kalmia. Mycelium growth of 9 isolates were inhibited by the leaf leachate. Colony diameter and biomass of the other 10 isolates were either increased or unaffected under the same conditions. Acidic pH of the culture medium(pH 3 and 4) inhibited some of the fungi, but a combination of acidic pH and the leaf leachate was more inhibitory. Thirteen isolates were able to form ectomycorrhizae with black spruce in presence of 25% leaf leachate in pure culture. Four isolates, Paxillus involutus(NF4), Cenococcum geophilum(GB12), Laccaria laccata(GB23), and E-strain(GB45) formed mycorrhizae more successfully than the others in presence of up to 50% Kalmia leaf leachate. Black spruce seedlings pre-inoculated with these fungi were grown with Kalmia leaf leachate and live Kalmia plants during a four month greenhouse experiment. Abundant mycorrhizae(77 - 91% of root tips) were developed on seedlings pre-inoculated with P. involutus, L. laccata and E-strain but relatively poor mycorrhization(32% of root tips) resulted with C. geophidum. Over 90 0 of the sham root mycorrhizae were attributed to the inoculated fungi although indigenous mycorrhizae also occurred on most seedlings. Persistence of the mycorrhizae was not affected by living Kalmia plants. Over 80% of the mycorrhizae on seedlings inoculated with P. involutus, L. laccata and E-strain and 53% of the mycorrhizae on seedlings inoculated with C. geophilum were attributable to the inoculant fungi. Control seedlings formed about 45% ectomycorrhizal short roots with indigenous fungi. The L. laccata and C. geophilum inoculated seedlings exhibited enhanced mycorrhizae formation in presence of Kalmia leaf leachate. Mycorrhizae formation with inoculant fungi was 4 - 15% lower at pH 4 than at pH 5, with the greatest inhibition occurring for L. laccata. Seedlings inoculated with P. involutus had the greatest shoot and root growth followed by L. laccata and E-strain inoculated seedlings. The P. involutus and L. laccata inoculated seedlings were significantly taller with more shoot dry biomass than the uninoculated(control) seedlings. E-strain inoculated seedlings had significantly higher shoot dry biomass and significantly lower number of first order lateral roots compared to the control but other growth parameters such as height, root dry weight and number of short root tips were not significantly different from the control. Seedlings inoculated with C. geophilum were not significantly different from the uninoculated seedlings in any of the growth parameters except for the number of first artier lateral roots which was significantly less than the control seedlings.