The Battle of Ostróda was a battle that took place on the 23rd of October 1628 in Ostróda during the Polish–Swedish War (1626–1629) between the Polish–Lithuanian Commonwealth commanded by Hetman Stanisław Koniecpolski and Jakub Butler against the Swedish Empire commanded by colonel Wolf Heinrich von Baudissin.

"[4] Koniecpolski, thanks to intercepting enemy correspondence, learned about the march from Pasłęk of a cavalry regiment under the command of Colonel Baudissin.

It is known that at the beginning of the campaign it had 1,500 horsemen, grouped in 12 companies, but during the fighting it suffered heavy losses and in October it numbered just over a thousand soldiers.

Baudissin, leading the charge, was wounded, while his regiment was dependent on several Polish (hussar) banners, previously hidden behind trees.

As Hetman Koniecpolski wrote with joy, "Baudis [in this case Baudissin] (...) fell into our hands with many of his considerable soldiers, and his regiment, which cost Gustav's strength and made many promises from him, is abolished."

The captured commander provided the hetman with information about the financing of Swedish troops by the Dutch.

The day after the battle, Ostróda was occupied by Swedish troops numbering 4,000 soldiers under the command of King Gustavus Adolphus.