A self-injection device with a miniaturized drug delivery portion is provided. The device includes a housing (10) having an interior volume and the drug delivery portion (20) has a volume enclosed within the housing. The drug delivery portion includes a reservoir (30) containing a fluid to be delivered to a user and a microneedle (22) in fluid communication with the reservoir and extendable through the housing. The drug delivery portion also includes a drive mechanism for expelling fluid from the reservoir through the microneedle, wherein the volume of the drug delivery portion is less than 40% of the interior volume of the housing. The volume of the drug delivery portion may be less than 30% of the interior volume of the housing.
