The office's latest estimate suggests that the German population grew by 90,000 people last year, with the numbers boosted by around 163,000 Poles, 95,000 Romanians, 51,000 Bulgarians, and 41,000 Hungarians all settling in the country in 2011.
But despite this positive development, authorities still believe that the population will continue to decline in coming decades, because Germans are not having enough babies.
The office says that there would need to be an average of 2.1 children per woman in order to sustain the current population level – but the current birth-rate is well below that at 1.4. Even the current rate of immigration to Germany is not enough to make up the deficit.
The number of live births in Germany dropped again last year, with 663,000 babies born - 15,000 or 2.2 percent less than in 2010. This compares with 852,000 deaths in 2011, also slightly fewer than in 2010, when 859,000 people died.
This deficit of births to deaths continues a four-decade old trend in Germany – more people have died than been born in the country since 1972. The number of marriages is also declining, with only 378,000 marriages last year - 4,000 fewer than 2010.
But demographers see no particular cause for alarm, since Germany still has the fourth highest population density in Europe - with around 230 people per square kilometre.