There is never a wrong time to invest in mutual funds for retirement. So, if you're still looking for the best mutual funds, the Zacks Mutual Fund Rank can be a great guide.

The easiest way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. Using the Zacks Mutual Fund Rank of over 19,000 mutual funds, we've identified three outstanding mutual funds that are ideally suited to help long-term investors pursue and achieve their retirement investing goals.

Let's take a look at some of our top-ranked mutual funds with the lowest fees.

ClearBridge Large Cap Growth IS (LSITX Quick QuoteLSITX - Free Report) : 0.66% expense ratio and 0.61% management fee. LSITX is a Large Cap Growth option; these mutual funds purchase stakes in numerous large U.S. companies that are expected to develop and grow at a faster rate than other large-cap stocks. LSITX has achieved five-year annual returns of an astounding 10.53%.

T. Rowe Price US Equity Research (PRCOX Quick QuotePRCOX - Free Report) . Expense ratio: 0.45%. Management fee: 0.33%. PRCOX is a Large Cap Blend fund, targeting companies with market caps of over $10 billion. These funds offer investors a stability, and are perfect for people with a "buy and hold" mindset. This fund has managed to produce a robust 11.61% over the last five years.

Hennessy Cornerstone Mid Cap 30 Investor (HFMDX Quick QuoteHFMDX - Free Report) : 1.36% expense ratio and 0.74% management fee. HFMDX is a Mid Cap Blend mutual fund, and usually features a portfolio with stocks of various styles and sizes, allowing for diversification within a strategy that focuses on mid cap companies. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 12.14% over the last five years.

There you have it. If your financial advisor had you put your money into any of our top-ranked funds, then they've got you covered. If not, you may need to talk.