How do I make case-insensitive queries on Mongodb?

Chris Fulstow's solution will work (+1), however, it may not be efficient, especially if your collection is very large. Non-rooted regular expressions (those not beginning with ^, which anchors the regular expression to the start of the string), and those using the i flag for case insensitivity will not use indexes, even if they exist.

An alternative option you might consider is to denormalize your data to store a lower-case version of the name field, for instance as name_lower. You can then query that efficiently (especially if it is indexed) for case-insensitive exact matches like:

db.collection.find({"name_lower": thename.toLowerCase()})

Or with a prefix match (a rooted regular expression) as:

db.collection.find( {"name_lower":
    { $regex: new RegExp("^" + thename.toLowerCase(), "i") } }
);

Both of these queries will use an index on name_lower.

I have solved it like this.

 var thename = 'Andrew';
 db.collection.find({'name': {'$regex': thename,$options:'i'}});

If you want to query for case-insensitive and exact, then you can go like this.

var thename =  '^Andrew$';
db.collection.find({'name': {'$regex': thename,$options:'i'}});

You'd need to use a case-insensitive regular expression for this one, e.g.

db.collection.find( { "name" : { $regex : /Andrew/i } } );

To use the regex pattern from your thename variable, construct a new RegExp object:

var thename = "Andrew";
db.collection.find( { "name" : { $regex : new RegExp(thename, "i") } } );

Update: For exact match, you should use the regex "name": /^Andrew$/i. Thanks to Yannick L.