mongoimport doesn't accept dbref

create a file called dbref-test.js with the following content. db.card.save({"_id": 1, "number": 123455}); db.person.save({"_id": 1, "name": "Joe", "card": DBRef("card", 1)}); And type in the following command. mongo mydb dbref-test.js mongoexport -d mydb -c person -o p.json mongoimport -d mydb -c person --upsert --file p.json You should see the following exception on mongoimport command exception:BSON representation of supplied JSON is too large: code FailedToParse: FailedToParse: Expecting quoted string: offset:64 FYI: p.json created by mongoexport contains this data. { "_id" : 1, "name" : "Joe", "card" : { "$ref" : "card", "$id" : 1 } }