In 1933 Bortkiewicz was forced to leave Germany again – being a Russian he was now facing persecution from the Nazi’s and saw his name being deleted from all music programmes. He returned to Vienna in 1935 where he established residence at Blechturmgasse 1 (appartment 5) and, most valuably of all, met his landlady, Frau Maria Cernas, who looked after him and his wife with touching, untiring friendliness. He lived here the rest of his life.

During these years Bortkiewicz suffered serious financial difficulties and was sought to ask for financial help from his friend Hugo van Dalen many times, which the pianist always gave freely. To earn some money Bortkiewicz translated from Russian into German the letters between Pjotr Tchaikovsky and Nadesdja von Meck. These letters were published as Die seltsame Liebe Peter Tschaikowsky’s und der Nadjeschda von Meck (Köhler & Amelang, Leipzig 1938). Van Dalen adapted Bortkiewicz’s book for a Dutch readership and published it as Rondom Tschaikowsky’s vierde symphonie (De Residentiebode 1938).

World War II was also a terrible time for Bortkiewicz and his wife. On 8 December 1945 he wrote to his friend Hans Ankwicz-Kleehoven (1883-1962), descriving how he was living: “I’m writing to you from my bathroom where we have crawled in because it is small and can be warmed on and off with a gas light (!). The other rooms cannot be used and I cannot touch my piano. This is now! What awaits us further? Life is becoming more and more unpleasant, merciless. I teach at the Conservatory with the temperature at 4 degrees, soon even less […]”. During the war Bortkiewicz composed one of his masterpieces, the piano sonata no. 2 opus 60, which he dedicated to Hans Ankwicz-Kleehoven. The sonata was first performed by the composer on 29 November 1942 in the Brahmssaal of the Musikverein in Vienna. Hugo van Dalen gave the Dutch premiere on 9 February 1944 in Amsterdam.

The second World War brought Bortkiewicz to the edge of despair and ruin. The greater part of his printed compositions, which were held by his German publishers, were destroyed in the bombing of German cities and hence he lost all his income from the sale of his music. Bortkiewicz and his wife were physically and mentally exhausted at the end of the war and were both in a desperate situation when there friend, the chief physician Dr. Walter Zdrahal, admitted the couple to the Franz Joseph Hospital in Vienna in order to treat them.

In the Autumn of 1945 Bortkiewicz was appointed director of a master class at the Vienna City Conservatory which helped the composer some of the financial security he so sought. In 1946 he composed his Six préludes opus 66 of which only two have so far been located. These préludes are dedicated to the Dutch pianist Helene Mulholland (1912-2000), who helped him, together with Hugo van Dalen, after the war by sending much needed food and clothes.

After his retirement in 1947 the community of Vienna awarded him an honorary pension. In the years after 1949 and primarily as a result of the war years, Bortkiewicz’s wife was diagnosed as suffering from manic depression which caused great concern for the composer.