How do I query a mongo document containing subset of nested array

Use the http://docs.mongodb.org/manual/core/aggregation-introduction/ for this. In the aggregation pipeline, consider the http://docs.mongodb.org/manual/reference/operator/aggregation/match/#pipe._S_match operator as your first pipeline stage. This is quite necessary to optimize your aggregation as you would need to filter documents that match the given criteria first before passing them on further down the pipeline. Next use the http://docs.mongodb.org/manual/reference/operator/aggregation/unwind/#pipe._S_unwind operator. This deconstructs the things array field from the input documents to output a document for each element. Each output document is the input document with the value of the array field replaced by the element. Another http://docs.mongodb.org/manual/reference/operator/aggregation/unwind/#pipe._S_unwind operation would be needed on the things.stuff array as well. The next pipeline stage would then filter dopcuments where the deconstructed things.stuff match the given min and max criteria. Use a http://docs.mongodb.org/manual/reference/operator/aggregation/match/#pipe._S_match operator for this. A http://docs.mongodb.org/manual/reference/operator/aggregation/group/#pipe._S_group operator is then required to group the input documents by a specified identifier expression and applies the accumulator expression http://docs.mongodb.org/manual/reference/operator/aggregation/push/#grp._S_push to each group. This creates an array expression to each group. Typically your aggregation should end up like this (although I haven't actually tested it but this should get you going in the right direction): db.collection.aggregate([ { "$match": { "things.stuff": { "$gt": 4, "$lte": 11 } } }, { "$unwind": "$things" }, { "$unwind": "$things.stuff" }, { "$match": { "things.stuff": { "$gt": 4, "$lte": 11 } } }, { "$group": { "_id": { "_id": "$_id", "things": "$things" }, "stuff": { "$push": "$things.stuff" } } }, { "$group": { "_id": "$_id._id", "things": { "$push": { "name": "$_id.things.name", "stuff": "$stuff" } } } } ])

If you need to transform the document on the client for display purposes, you could do something like this: Template.myTemplate.helpers({ transformedDoc: function() { // get the bounds - maybe these are stored in session vars var min = Session.get('min'); var max = Session.get('max'); // fetch the doc somehow that needs to be transformed var doc = SomeCollection.findOne(); // transform the thing.stuff arrays _.each(doc.things, function(thing) { thing.stuff = _.reject(thing.stuff, function(n) { return (n < min) || (n > max); }); }); // return the transformed doc return doc; } }); Then in your template: {{#each transformedDoc.things}}...{{/each}}