Bulk density is one of the main soil physical properties that affect root growth and development. This study aimed at characterizing bulk density distribution in a nitisol derived from volcanic ash, and assessing its effect on the rooting system of the East African Highlands Banana. Sixteen soil profiles (2m large x 1m depth) were dug at 40 cm from banana mat of second cycle at pre-flowering stage. At 10 cm increments, banana root density and soil bulk density were measured simultaneously. Soil bulk density was measured by gravimetric method, three replicates per soil depth. Soil texture and organic carbon content were also determined. Banana root density (roots.dm-2) was determined by overlying a 2 m² grid and counting roots in each 1 dm² grids. Results highlight a gradient in soil bulk density with values ranged between 0.85 to 1.08 g.cm-3. The lowest bulk density values were observed in the 40 cm topsoil, which also had most roots density (77%). Root density decreased sharply in deeper soil layers (<0.90 root.dm-² below 40 cm depth) with increase in clay content, and decrease in soil organic carbon content. To improve banana root growth and development in compacted soils, we recommend agricultural practices that decrease soil bulk density, especially the addition of soil organic matter throughout mulching, and tillage before banana planting.