Between the 2009 and 2013 seasons, the Houston Astros lost the most games by a team, with 498 losses.

Interpreted as:

most regular-season losses by a team from 2009 to 2013

	TEAM	L	W	L%	G	W%	AB	R	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Astros	498	312	.615	810	.385	27,350	3,062	6,788	1,335	129	639	2,883	2,153	232	6,079	546	220	30,221	10,298	2,103	307	179	134	618	.248	.307	.377	.683
2	Cubs	453	356	.560	809	.440	27,456	3,261	6,839	1,438	146	767	3,092	2,382	278	6,088	337	165	30,555	10,870	2,351	270	169	168	626	.249	.314	.396	.710
3	Mariners	451	359	.557	810	.443	27,425	2,952	6,570	1,250	101	707	2,813	2,310	186	6,169	509	170	30,303	10,143	2,058	194	188	147	533	.240	.301	.370	.671
4	Royals	449	361	.554	810	.446	27,993	3,416	7,461	1,429	194	637	3,265	2,196	200	5,082	641	207	30,815	11,189	2,260	201	225	155	669	.267	.322	.400	.722
5	Pirates	445	364	.550	809	.450	27,122	3,118	6,651	1,356	168	689	2,985	2,364	252	6,341	452	214	30,242	10,410	2,213	317	187	176	584	.245	.310	.384	.693
6	Marlins	440	370	.543	810	.457	27,497	3,238	6,838	1,344	162	692	3,070	2,540	260	6,305	489	172	30,814	10,582	2,198	327	190	203	573	.249	.316	.385	.701
7	Indians	436	374	.538	810	.462	27,554	3,535	6,986	1,450	121	750	3,348	2,738	320	6,034	491	186	30,987	10,928	2,321	154	221	131	616	.254	.326	.397	.722
8	Mets	436	374	.538	810	.462	27,527	3,314	6,985	1,419	181	600	3,150	2,614	226	5,742	575	196	30,933	10,566	2,200	344	222	241	581	.254	.321	.384	.705
9	Twins	435	376	.536	811	.464	27,789	3,532	7,211	1,403	151	699	3,347	2,622	226	5,535	432	169	31,042	11,013	2,253	182	223	163	673	.259	.326	.396	.722
10	Orioles	433	377	.535	810	.465	27,937	3,519	7,217	1,412	83	910	3,365	2,289	231	5,629	370	154	30,799	11,525	2,405	133	209	141	696	.258	.318	.413	.730
11	Rockies	424	386	.523	810	.477	27,648	3,773	7,326	1,433	232	851	3,587	2,677	213	6,169	535	210	31,109	11,776	2,516	346	225	207	569	.265	.332	.426	.758
12	Padres	422	388	.521	810	.479	27,215	3,165	6,625	1,266	166	631	2,986	2,631	261	6,232	649	203	30,627	10,116	2,063	323	197	233	541	.243	.314	.372	.686
13	Blue Jays	422	388	.521	810	.479	27,774	3,724	7,008	1,463	114	1,035	3,548	2,527	241	5,750	497	177	30,888	11,804	2,612	133	213	137	594	.252	.318	.425	.743
14	Diamondbacks	419	391	.517	810	.483	27,597	3,583	7,015	1,510	180	820	3,436	2,749	221	6,484	476	228	31,026	11,345	2,510	256	203	245	556	.254	.325	.411	.736
15	Nationals	417	392	.515	809	.485	27,403	3,376	6,923	1,338	143	814	3,222	2,533	262	6,268	482	182	30,729	10,989	2,295	335	196	193	586	.253	.320	.401	.721
16	White Sox	416	394	.514	810	.486	27,530	3,476	7,058	1,226	105	874	3,330	2,348	324	5,343	568	261	30,595	11,116	2,205	186	207	126	648	.256	.320	.404	.724
17	Brewers	400	410	.494	810	.506	27,594	3,672	7,163	1,388	183	908	3,511	2,510	369	5,953	543	183	31,000	11,641	2,479	331	196	189	584	.260	.327	.422	.749
18	Athletics	390	420	.481	810	.519	27,532	3,547	6,908	1,431	137	739	3,355	2,686	237	5,766	602	189	30,856	10,830	2,307	156	245	110	583	.251	.320	.393	.714
19	Angels	380	430	.469	810	.531	27,747	3,731	7,355	1,401	147	834	3,554	2,427	239	5,544	603	234	30,858	11,552	2,382	219	226	162	667	.265	.327	.416	.743
20	Reds	375	435	.463	810	.537	27,629	3,565	7,049	1,407	124	856	3,395	2,654	307	6,108	440	195	31,206	11,272	2,387	402	214	242	543	.255	.325	.408	.733
21	Giants	374	436	.462	810	.538	27,577	3,271	7,090	1,408	189	615	3,077	2,279	220	5,554	403	176	30,658	10,721	2,212	340	242	225	635	.257	.316	.389	.705
22	Dodgers	374	435	.462	809	.538	27,383	3,377	7,090	1,335	136	636	3,198	2,595	263	5,641	516	210	30,851	10,605	2,107	387	223	288	634	.259	.327	.387	.714
23	Red Sox	370	440	.457	810	.543	28,154	4,152	7,631	1,747	127	969	3,960	2,833	284	5,873	516	148	31,651	12,539	2,843	128	252	212	645	.271	.341	.445	.786
24	Tigers	368	443	.454	811	.546	27,957	3,803	7,590	1,421	163	843	3,650	2,649	241	5,580	284	126	31,283	11,866	2,427	212	224	213	693	.271	.337	.424	.762
25	Phillies	364	446	.449	810	.551	27,738	3,599	7,068	1,386	167	841	3,454	2,559	306	5,542	512	125	31,092	11,311	2,394	293	196	250	563	.255	.323	.408	.730