I'm trying to negate an $and clause with MongoDB and I'm getting a MongoError: invalid operator: $and message back. Basically what I want to achieve is the following: query = { $not: { $and: [{institution_type:'A'}, {type:'C'}] } } Is this possible to express in a mongo query? Here is a sample collection: { "institution_type" : "A", "type" : "C" } { "institution_type" : "A", "type" : "D" } { "institution_type" : "B", "type" : "C" } { "institution_type" : "B", "type" : "D" } What I want to get back is the following: { "institution_type" : "A", "type" : "D" } { "institution_type" : "B", "type" : "C" } { "institution_type" : "B", "type" : "D" }