Altes Krematorium Hamburg-Alsterdorf, Former crematorium in Alsterdorf, Hamburg, Germany

Altes Krematorium Hamburg-Alsterdorf is a heritage crematorium in Hamburg-Nord, distinguished by its octagonal central building featuring Romanesque design elements. The structure includes a grand staircase ascending to a tall ceremonial hall where funeral services were once held.

The cremation society's 1888 competition was won by Ernst Paul Dorn with an octagonal design; the foundation stone was laid on 18 October 1890 and the building inaugurated on 22 August 1891. Legal delays, resolved after the 1892 cholera epidemic, meant the first cremation only took place on 19 November 1892. From 1932 the Ohlsdorf main cemetery crematorium replaced it, though urn burials continued into the early 1950s.

The crematorium's 1901–1904 urn grove, designed by Wilhelm Cordes, was laid out as an artificial landscape of small hills, water, rocks and winding paths modelled on the old part of Ohlsdorf Cemetery. The artist Anita Rée was originally buried there. A red sandstone terrace followed in 1911 under Ricardo Bahre.

The building stands at Alsterdorfer Straße 523, between Hamburg-Ohlsdorf station and the Alster, beside the Ohlsdorf cemetery. It has housed a private school and day nursery since 2009, so the interior is not open to visitors; the octagonal brick building and the 25 m chimney can be seen from the street. The former urn grove and terrace are largely obscured by later construction.

The 25-metre chimney was built double-walled and served to ventilate the building as well as to meet construction rules; its facade imitates towers of the Italian Renaissance, like those of Tuscan palazzi or Hamburg's Alte Post of 1847.