To determine role of transrectal ultrasound in follow up of patients who underwent ILC. 65 men with lower urinary tract symptoms caused by BPH underwent ILC treatment with Indigo 830 diode laser system. 53 patients have already completed 1,3 and 6 months follow up. The study group was assessed prior the treatment. The following criteria are evaluated: uroflow rate, post voiding residual volume, prostate volume, changes in the prostate echostructure following the treatment, International Prostate Symptoms Score (IPSS), Quality of Life (QL). Patients were divided in two groups - presenting with and without of urinary retention. In the group presenting with urinary retention prostate volume has changed from 51,7 cc at the initial measurement to 48,5 cc at 6 months, in the remaining group we recorded volumes of 45,3 cc and 47,9 cc respectively. In the group without urinary retention residual urine volume decreased from 93 cc initially to 65 cc at 6 months. IPSS score decreased from 21.7 initially to 11.1 respectively. QL score decreased from 4.4 initially and remains stable after 3 months 2.6 and 2.8 - 6/12. In one patient we showed cystic lesion formation within peripheral zone containing blood clot and several periurethral small cysts formation were observed around urethra. TRUS allows to exclude any patients with prostate carcinoma which is not followed by the rise of PSA level.