The couple is currently holidaying in The Hamptons with Kardashian's sister Khloe as part of their new reality show Kourtney and Khloe Take The Hamptons, but their summer (14) trip was disrupted last month (Jul14) after a thief grabbed the case from Kardashian and Disick's bedroom.
They filed a police report with local authorities in the town of Southampton, revealing the money was taken between 1 and 4 July (14).
Cops have confirmed nothing else was stolen in the raid and there was no sign of forced entry.
According to editors at Tmz.com, the reality stars suspect the theft was an inside job as it is the third such incident to hit their family in recent months.
Kourtney Kardashian first contacted police in February (14) after $50,000 (£29,412) in cash was taken from her home in Calabasas, California, while her younger sister Khloe Kardashian became the second theft victim in early March (14), when an estimated $250,000 (£147,059)-worth of jewellery was taken from her Tarzana, California home in the midst of her move to a new property.