To identify which patients will have difficulty during morcellation in holmium laser enucleation of the prostate (HoLEP), we analyzedthe association of preoperative factors with morcellation efficiency retrospectively. Between March 2015 andMay 2019, 129 patients with benign prostatic hyperplasia (BPH) underwent HoLEP at our institution. Based on the morcellation efficiency (morcellation volume per minute), they were classifiedinto easy (≥3 g/min, n＝81) andd ifficult (＜3 g/min, n＝48) groups. In patients who underwent computed tomography (CT) before the surgery, CT values of the prostatic adenomas were measured. The preoperative parameters were comparedbetween the two groups. Comparedwith the easy group, the morcellation time in the difficult group was significantly longer (median, 11 vs 18.5 min, ＜0.001), though prostate volume was not significantly different (median, 76.3 vs 69.3 ml, p＝0.116). The body mass index (BMI) was significantly lower in the difficult group (median, 23.2 vs 21.9 kg/m2, p＝0.007), andit was positively correlatedwith morcellation efficiency. The difference between the maximum andaverage CT values tended to be lower in the difficult group (median, 43.6 vs 39.2 HU, p＝0.066), andit was positively correlatedwith BMI andmorcellation efficiency. Morcellation appearedto be difficult in BPH patients with low BMI because of the homogeneous hardness of prostatic adenoma.