The Colorado Rockies allowed the most runs by a team in May 2012, with 167 runs.

	TEAM	R	MONTH	G	W%	W	L	ERA	SO	SHO	SV	IP	H	ER	HR	BB	HBP	IBB	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	H/9
1	Rockies	167	May 2012	28	.357	10	18	5.66	231	0	3	245.0	298	154	34	108	9	12	1,120	15	8.49	3.97	2.14	1.25	20.6	9.6	1.66	.358	6.13	10.95
2	Indians	152	May 2012	30	.533	16	14	4.77	195	1	12	268.0	266	142	22	120	11	2	1,168	11	6.55	4.03	1.63	0.74	16.7	10.3	1.44	.298	5.10	8.93
3	Twins	146	May 2012	28	.429	12	16	4.96	173	0	6	247.0	266	136	35	84	11	7	1,053	11	6.30	3.06	2.06	1.28	16.4	8.0	1.42	.308	5.32	9.69
4	Cardinals	145	May 2012	29	.448	13	16	4.72	208	1	5	257.1	287	135	22	93	8	8	1,138	12	7.27	3.25	2.24	0.77	18.3	8.2	1.48	.328	5.07	10.04
5	Rangers	144	May 2012	28	.500	14	14	4.30	227	0	5	251.0	231	120	40	92	5	2	1,059	6	8.14	3.30	2.47	1.43	21.4	8.7	1.29	.275	5.16	8.28
6	Braves	138	May 2012	29	.483	14	15	4.48	209	1	9	261.1	252	130	35	98	12	8	1,118	7	7.20	3.38	2.13	1.21	18.7	8.8	1.34	.284	4.75	8.68
7	Orioles	138	May 2012	28	.536	15	13	4.16	215	0	10	268.0	276	124	38	74	9	8	1,145	4	7.22	2.49	2.91	1.28	18.8	6.5	1.31	.294	4.63	9.27
8	Phillies	133	May 2012	29	.552	16	13	4.35	250	2	6	262.2	267	127	42	62	6	5	1,088	4	8.57	2.12	4.03	1.44	23.0	5.7	1.25	.309	4.56	9.15
9	Mets	133	May 2012	28	.536	15	13	4.64	219	1	10	246.1	256	127	30	77	6	2	1,060	6	8.00	2.81	2.84	1.10	20.7	7.3	1.35	.310	4.86	9.35
10	Padres	129	May 2012	28	.357	10	18	4.36	195	0	6	247.2	243	120	26	105	2	13	1,066	7	7.09	3.82	1.86	0.94	18.3	9.8	1.41	.294	4.69	8.83
11	Cubs	128	May 2012	27	.370	10	17	4.47	181	0	5	241.2	225	120	32	107	13	8	1,049	7	6.74	3.98	1.69	1.19	17.3	10.2	1.37	.270	4.77	8.38
12	Blue Jays	127	May 2012	28	.536	15	13	4.42	212	3	5	248.2	234	122	28	122	11	4	1,084	13	7.67	4.42	1.74	1.01	19.6	11.3	1.43	.290	4.60	8.47
13	Red Sox	126	May 2012	29	.517	15	14	3.93	210	0	9	268.0	256	117	28	97	15	2	1,133	9	7.05	3.26	2.16	0.94	18.5	8.6	1.32	.291	4.23	8.60
14	Tigers	126	May 2012	29	.448	13	16	4.13	255	1	7	250.2	248	115	31	66	5	3	1,053	7	9.16	2.37	3.86	1.11	24.2	6.3	1.25	.312	4.52	8.90
15	Diamondbacks	123	May 2012	28	.393	11	17	4.17	180	0	7	243.2	255	113	25	77	10	5	1,044	6	6.65	2.84	2.34	0.92	17.2	7.4	1.36	.306	4.54	9.42
16	White Sox	122	May 2012	29	.621	18	11	4.20	201	0	6	257.1	239	120	31	89	16	5	1,092	9	7.03	3.11	2.26	1.08	18.4	8.2	1.27	.275	4.27	8.36
17	Astros	122	May 2012	28	.464	13	15	3.72	215	0	7	251.2	260	104	32	88	8	9	1,096	9	7.69	3.15	2.44	1.14	19.6	8.0	1.38	.303	4.36	9.30
18	Brewers	119	May 2012	28	.429	12	16	3.65	233	0	5	256.1	248	104	18	87	8	7	1,092	6	8.18	3.05	2.68	0.63	21.3	8.0	1.31	.308	4.18	8.71
19	Royals	117	May 2012	28	.536	15	13	4.07	207	0	8	252.0	255	114	25	94	9	5	1,081	5	7.39	3.36	2.20	0.89	19.1	8.7	1.38	.308	4.18	9.11
20	Giants	116	May 2012	29	.517	15	14	3.39	222	0	10	263.0	237	99	19	101	6	13	1,120	9	7.60	3.46	2.20	0.65	19.8	9.0	1.29	.282	3.97	8.11
21	Yankees	115	May 2012	28	.500	14	14	3.97	210	0	8	245.0	252	108	38	79	7	2	1,051	8	7.71	2.90	2.66	1.40	20.0	7.5	1.35	.298	4.22	9.26
22	Marlins	115	May 2012	29	.724	21	8	3.57	192	1	12	265.0	247	105	13	83	8	9	1,099	7	6.52	2.82	2.31	0.44	17.5	7.6	1.25	.291	3.91	8.39
23	Mariners	113	May 2012	29	.414	12	17	3.84	192	1	3	253.1	217	108	30	83	8	2	1,043	8	6.82	2.95	2.31	1.07	18.4	8.0	1.18	.256	4.01	7.71
24	Pirates	110	May 2012	28	.536	15	13	3.58	203	0	10	249.0	236	99	24	85	7	8	1,053	8	7.34	3.07	2.39	0.87	19.3	8.1	1.29	.289	3.98	8.53
25	Athletics	110	May 2012	27	.407	11	16	3.91	169	0	6	241.2	233	105	25	100	10	7	1,046	7	6.29	3.72	1.69	0.93	16.2	9.6	1.38	.280	4.10	8.68