The actor revealed the poodle went missing near the couple’s home in Montecito, California.
Mighty is chipped and his collar has a number to call, Bloom said, as he offered a reward for the dog’s safe return.
The Pirates Of The Caribbean star asked fans to “only send REAL INFO”.
Alongside pictures of the dog, Bloom wrote on Instagram: “MIGHTY IS MISSING in Montecito California, he is chipped and his collar has a number to call – if you take him to your local vet or shelter or police station he can be traced back to me for a reward.
"Please only send REAL INFO my heart is already broken so please don’t add insult to injury.”
Bloom, 43, and Perry, 35, also own another poodle called Nugget. The dogs make frequent appearances on the stars’ social media accounts.
The couple’s famous friends sent their best wishes in the comments section of Bloom’s post.
Danish supermodel Helena Christensen said: “Oh I’m so so sorry, I can’t imagine the pain you’re going through. Mighty must and will be found!!”
Bloom and Perry are currently expecting their first child together.
The pop star announced her pregnancy back in March by revealing her bump in the music video for her single Daisies.
Bloom is already father to a son, nine-year-old Finn, from his former relationship with Miranda Kerr.
Additional reporting by Press Association