B.Grincevičiūtė was born on 28 November 1911 in Stolaukelis village of Vilkaviškis district. The singer‘s father Andrius Grincevichius descended from a family branch that had settled down and spread around Smolensk and Ukrainian lands several centuries ago, and her mother Vanda Grincevičiūtė belonged to the noblemen Grincevičius‘s family that had been living in owned by them Ilguva during more than 180 years. Andrius Grincevičius and Vanda Grincevičienė had six children: Henrikas (1901), Liudvikas (1904), Vaitiekus (1910), Beatričė (1911), Stasys (1915), and Kristina (1918). After Beatričė father’s death in 1917, she spent her childhood at the Ilguva estate, which belonged at that time to Professor Emil Mlynarsky, the singer aunt‘s husband. E. Mlynarsky was an important person in the cultural life of Warsaw of those days: he had established the Philharmonic Society, was the first conductor and director of the Great Opera and Music Institute (Conservatory) of Warsaw. E. Mlynarsky became a sponsor of S. Šimkus and B. Grincevičiūtė‘s studies.
It was at Ilguva where the first Beatričė‘s acquaintance with music took place. Her uncle Emil, having noticed the girl‘s exceptional musical gifts, decided to support her further studies in Warsaw. In the year 1921, Beatričė studied at the Warsaw School for the blind, and in the year 1924 continued her education at the Warsaw Institute for blind and mute people, where after general education lessons children could also take music lessons. Here the singer was learning to play the violin; however, the piano was closer to her heart, so later she passed on to the piano specialty. The girl was singing in the institute chorus directed by Prof. Z. Bilinski. Having noticed Beatričė‘s voice, the professor often nominated the singer to sing solo parts. In 1928, Beatričė completed six years of the institute and returned to Lithuania. In 1931, she started working as a governess at the Institute for blind people and tried to continue her singing studies at the Conservatory directed by the composer J. Gruodis, though unsuccessfully. In 1934, B. Grincevičiūtė started studying a vocal art at the People‘s Conservatory run by E. Laumenskienė, in a class of the singer Antanina Binkevičiūtė. Three years’ studies were crowned with the first Beatričė‘s concert on 24 November 1937 on Kaunas radio , after which the singer‘s name became known all over Lithuania. Six years later - on 6 March 1943 – the singer returned once again to J.Gruodis‘s Conservatory, this time as a soloist. It was the first Beatričė‘s recital. In 1944, she became a soloist of the Lithuanian National Philharmonia (Kaunas section) and worked this work in Kaunas until the year 1946. The same year, B. Grincevičiūtė moved to live in Vilnius and started working as a soloist of the Lithuanian radio (till 1959). In 1966, the singer was invited to work in a Radio Committee Commission for approving musical records. The work in the Commission continued until the year 1984.
A whole B. Grincevičiūtė‘s life was entailed by extensive concert activity in collaboration with the composer B. Dvarionas, actor L. Noreika, pianist H. Znaidzilauskaitė, singer Vl. Mikštaitė. A repertoire of the concerts was very wide and diverse. We can count about 1000 musical compositions performed, beginning with folk songs and ending with original songs of classical composers. Beside the extensive concert activity, the singer was working pedagogical work at nursery schools , and since the year 1974 she worked as an illustrator at the art school of M.K. Čiurlionis.
B. Grincevičiūtė died on 28 November 1988 in Vilnius. She was buried at the Antakalnis cemetery.