In Mazowieckie Voivodship in 2021 a decrease in the number of population was recorded. One of the factors influencing the size of the population is natural increase, which in 2021 was negative – there were 19.5 thousand more deaths than live births. The second factor affecting the population is net migration. In 2021, permanent net migration was positive and amounted to 13.0 thousand, however it did not compensate for population decline.