Leifsonia xyli subsp. xyli (Lxx) causing ratoon stunting disease (RSD) substantially reduces yield globally in sugarcane, an economically important widely cultivated crop in Nigeria. However, the presence of RSD has not been conclusively determined in Nigeria. Thus, the effects of RSD on yield of sugarcane cultivars grown in Nigeria are unknown and as such investigated in this study. L. xyli subsp. xyli inoculated and uninoculated cuttings from each eighteen sugarcane cultivars were planted for 12 months and nine months for the first plant and ratoon crops respectively in the screenhouse. Number of mature stalks, stalk length, stalk diameter, weight of matured stalks, sucrose contents (%) and total sucrose yield were used to compare between the growth and yield of inoculated and uninoculated cultivars. Most growth and yield parameters were reduced in the Lxx-inoculated sugarcane plants compared with the uninoculated plants. Total sucrose per cultivar was higher in uninoculated than inoculated plants with SP71–6180 (uninoculated) and Co6806 (inoculated) having the highest and lowest yields of 315.21 g and 105.48 g respectively. Stalk dimensions (length and diameter), stalk weight (cane yield) and total amount of sucrose per cultivar (sucrose yield) in inoculated cultivars were significantly reduced more in the ratoon than plant crops. RSD introduction could result in a yield loss between 4.02% and 41.43% on all the sugarcane cultivars commonly grown in Nigeria.