The radioisotopic composition of different soil types of the Vilnius city (54°40’N, 25°20’E), the capital and the biggest city of Lithuania, was identified. The specific activities of natural radionuclides in the soil were measured with a gamma spectrometric system containing a HPGe detector. The specific activities of natural radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K in samples of different granulometric composition were measured. The maximum values of ⁴⁰K were identified in the southeastern and eastern parts of the city (about ⁴⁷⁹ Bq/kg) and the minimum values in the northern and western parts (about ²⁰⁰ Bq/kg). The maximum values of ²²⁶Ra and ²³²Th specific activities were measured in the southern and southeastern regions (²³ Bq/kg and 8 Bq/kg, respectively) and the minimum values in the central part of the city (⁷ Bq/kg and ³ Bq/kg, respectively). The contribution to the external equivalent dose rate of separate gamma emitters ²²⁶Ra, ²³²Th and 40K was estimated.
In the Vilnius city, the radiation of the equivalent dose rate makes up on average 12 nSv/h due to ⁴⁰K present in the soil, ⁶ nSv/h due to ²²⁶Ra, ³ nSv/ h due to ²³²Th.

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