Virus SARS-COV-2 first appeared in China in the December of 2019. The disease that originated from this virus was named COVID-19. Considering that at the time the disease was still unknown and the speed of its spread between humans was extremely quick, this led to the virus taking over the whole world. Around the globe drastic measures were taken in order to stop further spread from the infection. The appearance of COVID-19 depended on following given measures and the overall immunity, age and effectiveness of an individual. The bases for stopping the spread of infection consisted of wearing face masks, hand disinfection, avoiding physical contact and lockdown. Many businesses moved their operations to the virtual world. Schools would also follow this path, with primary and high schools organizing their classes through internet and television. Goals of this research: This research dealt with the appearance of COVID-19 disease in pupils in Dubrovnik-Neretva County, depending on a couple of factors: gender, location of the school pupils go to (urban or rural environments), how effective the epidemic measures of wearing face mask were and the epidemic connection. Subjects and methods: Research includes the whole population of pupils (high and primary school) in Dubrovnik-Neretva County who were tested in the period from March 18.2020. to June 30.2021. due to suspicions of having COVID-19. Total number of pupils in the area Dubrovnik-Neretva County is 13958. Number of pupils infected with COVID-19 disease is 1290, out of which 656 are male and 634 are female. The results: With the conducted research it is determined that 50.90% boys and 49.10% girls were infected and thus it can be seen that gender doesn’t make a big difference. When comparing pupils with different age, in the gap from 6 to 18 years old, it is shown that pupils with ages 16 (11.60%), 17 (10.30%) and 13 (10.30%) were most affected by the disease. Following close behind are ages 14 (9.70%) and 15 (9.50%). The appearance of COVID-19 disease in schools that are located in urban environment amongst high school pupils (12.71%) is statistically higher than the appearance amongst higher grade pupils in primary school (9,02%). Likewise, a significant difference in the appearance of the disease was shown between pupils of higher grade (9.02%) and lower grade (6.70%) in primary schools, based in urban environment. No significant difference was detected in the appearance of the disease between primary and high schools in rural environment, even with given protective measure for wearing face mask. Primary school pupils of lower grades (1.-4.) don’t wear face masks, while higher grade pupils (5.-8.) and high school pupils wear them. Pupils that tested positive on COVID-19 from first to fourth and from fifth to eight grades of primary schools reported more often that the source of their infection was a contact with a family member, while high school pupils from first to fourth grades reported that their source of infection was someone from school or unknown. Conclusion: Keeping distance, hand hygiene and wearing face mask are three bases for measures that can help limit the spread of the virus. Every close contact was considered dangerous and keeping a physical distance between each other was desirable and rounding up a large number of people was absolutely unacceptable. All of the above is directly in contrast with the nature of children who like to hang out and spend time together which affected the effectiveness of the defense measures.