Evaluation of puberty onset and menarche in girls in Bratislava region in the years 2006-2007 and 2011-2013.Regional retrospective epidemiological study.1st Department of Gynaecology and Obstetrics, School of Medicine, Comenius University and University Hospital Bratislava, Slovenské republika.A study in two periods was performed. The first was in the years 2006-2007 and the second in 2011-2013. Together 217 girls aged 7-16 were enrolled. Secondary sexual characteristics according to Tanner were evaluated. Ultrasound examination of the uterus and ovaries was performed. The results were statistically evaluated by software Statistical Package for Social Sciences (SPSS) by age, and compared to results of Slovak study held in the years 1976-1980.The mean age of menarche onset of girls in the group was 12.37. Pubarche and adrenarche onset were at 10.7 and 11.7 year respectively. Thelarche onset was at 10.9 year. Development of secondary sexual characteristics significantly correlated with ultrasound parameters of internal genitalia and with age of menarche. Average ultrasound parameters increases with age to 15 years. Significant changes were for average anteroposterior uterine size in 11 and 13 years old girls, for proportion corpus/cervix of the uterus in 9 and 11 years old girls and for average ovarian volume in 9, 11, 14 and 15 years old girls.The results from our study comparing to those from study held in 1976-1980 shows continuous secular trend in Bratislava region.age of menarche, secular trend, puberty, secondary sexual characteristics.