Objective To determine the effectiveness and safety of pneumatic balloon dilatation in patients with achalasia. Methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL, issue 1, 2007), MEDLINE or PUBMED (1978-2007), Embase (1978-2007), OVID Database (1978-2007), Chinese Biological Medicine Database (CBMDisc, 1978-2007), CNKI (1979-2007), Chinese VIP Database (1989-2007) and Wanfang Database (1978-2007). We also checked the reference lists of retrieved articles and relevant proceedings. We used the methods recommended by The Cochrane Collaboration to conduct this systematic review. Results Twenty four trials involving 1045 patients were included. Meta-analyses showed that the short-term total effective rate was much higher with pneumatic dilatation than intrasphincteric botulinum toxin injection (P=0.0007). The long-term total effective rate was higher with pneumatic dilatation compared to intrasphincteric botulinum toxin injection (P=0.005). Intrasphincteric botulinum toxin injection was superior to pneumatic dilatation in terms of clinical relapse rate (Plt;0.0001). Our analyses of complications and adverse effects found that pneumatic dilatation was superior to intrasphincteric botulinum toxin injection (P=0.0008), and endoscopic sphincterotomy was superior to balloon dilatation (P=0.0006). Conclusions The limited current evidence shows that: pneumatic dilatation is safe and effective for the short- or long-term treatment of achalasia.