The Pittsburgh Pirates had the lowest winning percentage by a team in 2010, winning 35.2 percent of the time.

	TEAM	W%	SEASON	W	L	G	AB	R	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Pirates	.352	2010	57	105	162	5,386	587	1,303	276	27	126	570	463	33	1,207	87	36	5,973	2,011	429	58	33	28	119	.242	.304	.373	.678
2	Mariners	.377	2010	61	101	162	5,409	513	1,274	227	16	101	485	459	39	1,184	142	39	5,989	1,836	344	42	40	33	110	.236	.298	.339	.637
3	Diamondbacks	.401	2010	65	97	162	5,473	713	1,366	301	34	180	691	589	39	1,529	86	41	6,183	2,275	515	41	41	45	113	.250	.325	.416	.740
4	Orioles	.407	2010	66	96	162	5,554	613	1,440	264	21	133	577	424	54	1,056	76	34	6,108	2,145	418	31	45	32	154	.259	.316	.386	.702
5	Royals	.414	2010	67	95	162	5,604	676	1,534	279	31	121	640	471	35	905	115	50	6,208	2,238	431	45	53	25	152	.274	.331	.399	.730
6	Indians	.426	2010	69	93	162	5,487	646	1,362	290	20	128	601	545	64	1,184	91	33	6,165	2,076	438	36	33	34	118	.248	.322	.378	.700
7	Nationals	.426	2010	69	93	162	5,418	655	1,355	250	31	149	634	503	60	1,220	110	41	6,099	2,114	430	71	47	36	125	.250	.318	.390	.708
8	Cubs	.463	2010	75	87	162	5,512	685	1,414	298	27	149	658	479	50	1,236	55	31	6,139	2,213	474	60	38	32	124	.257	.320	.401	.721
9	Astros	.469	2010	76	86	162	5,452	611	1,348	252	25	108	577	415	33	1,025	100	36	6,004	1,974	385	75	29	27	130	.247	.303	.362	.665
10	Brewers	.475	2010	77	85	162	5,606	750	1,471	293	33	182	710	546	81	1,216	81	26	6,303	2,376	508	35	35	35	115	.262	.335	.424	.759
11	Mets	.488	2010	79	83	162	5,465	656	1,361	266	40	128	625	502	46	1,095	130	44	6,144	2,091	434	74	57	53	101	.249	.314	.383	.697
12	Dodgers	.494	2010	80	82	162	5,426	667	1,368	270	29	120	621	533	46	1,184	92	50	6,140	2,056	419	85	50	57	123	.252	.322	.379	.700
13	Angels	.494	2010	80	82	162	5,488	681	1,363	276	19	155	656	466	52	1,070	104	52	6,085	2,142	450	42	37	28	125	.248	.311	.390	.702
14	Marlins	.494	2010	80	82	162	5,531	719	1,403	294	37	152	686	514	55	1,375	92	26	6,194	2,227	483	51	43	42	107	.254	.321	.403	.724
15	Tigers	.500	2010	81	81	162	5,643	751	1,515	308	32	152	717	546	41	1,147	69	30	6,312	2,343	492	41	41	50	118	.268	.335	.415	.750
16	Athletics	.500	2010	81	81	162	5,448	663	1,396	276	30	109	619	527	47	1,061	156	38	6,116	2,059	415	43	51	16	129	.256	.324	.378	.702
17	Rockies	.512	2010	83	79	162	5,530	770	1,452	270	54	173	741	585	47	1,274	99	41	6,265	2,349	497	56	47	53	103	.263	.336	.425	.760
18	Blue Jays	.525	2010	85	77	162	5,495	755	1,364	319	21	257	732	471	55	1,164	58	20	6,071	2,496	597	16	34	25	114	.248	.312	.454	.766
19	Cardinals	.531	2010	86	76	162	5,542	736	1,456	285	18	150	689	541	50	1,027	79	41	6,239	2,227	453	66	40	78	124	.263	.332	.402	.733
20	White Sox	.543	2010	88	74	162	5,484	752	1,467	263	21	177	710	467	79	922	160	74	6,118	2,303	461	50	38	23	148	.268	.332	.420	.752
21	Red Sox	.549	2010	89	73	162	5,646	818	1,511	358	22	211	782	587	47	1,140	68	17	6,355	2,546	591	29	46	43	130	.268	.339	.451	.790
22	Rangers	.556	2010	90	72	162	5,635	787	1,556	268	25	162	740	511	45	986	123	48	6,298	2,360	455	53	54	37	129	.276	.338	.419	.757
23	Padres	.556	2010	90	72	162	5,434	665	1,338	236	24	132	630	538	50	1,183	124	50	6,147	2,018	392	79	46	67	106	.246	.317	.371	.689
24	Braves	.562	2010	91	71	162	5,463	738	1,411	312	25	139	699	634	51	1,140	63	29	6,252	2,190	476	69	35	50	136	.258	.339	.401	.740
25	Reds	.562	2010	91	71	162	5,579	790	1,515	293	30	188	761	522	68	1,218	93	43	6,285	2,432	511	66	50	34	113	.272	.338	.436	.774